A "serious" - and previously unknown - security breach on the 1981 Springbok tour meant two members of the South African party narrowly escaped being sent home.
The senior players were responsible for a prank that backfired and sparked a top-level alert after getting annoyed with team doctor Augie Cohen.
Annoyed by the amount of time Cohen was spending on the golf course, the pair carried out a mock raid on his hotel room.
Ramifications included the bomb squad being scrambled amid fears the tourists had been targeted by poisonous gas.
The revelations have emerged as surviving members of the Springbok team prepare to mark the 40th anniversary of the tour in the middle of 2021.
Star flanker Theuns Stofberg opened up from his home in Stellenbosch, about 50km east of Cape Town.
"Our team doctor was a keen golfer and if he had a chance he would go and have a quick round of golf," Stofberg told the Herald.
"So some of the guys, Divan Serfontein and Ray Mordt, walked around town and they got these stink bombs. Back at the hotel they got to his room, got the key, and let off these stink bombs.
"[The doctor] was quite scared in the circumstances. When he got in his room and smelt that smell, he thought it was some kind of gas or something going on against us. There was great alarm, the police came and it was quite an incident."
Stofberg – who captained the Springboks in their 14-9 first test loss at Lancaster Park, Christchurch – described the incident as "serious" and said even the police were annoyed.
In his memoir, Stories from the Touchline, he wrote: "If it wasn't for the fact that the Springboks couldn't do without those two key players, they would have followed the rest of the tour in the early-morning hours on TV in South Africa. The team management was on the verge of sending them home on the first available flight because of all the drama they had caused."
When Cohen returned to his room, Stofberg continued, "We heard him cry: 'Help! Gas! Poisonous gas! They want to kill me!'.
"Alarms went off and there were policemen everywhere. The bomb squad arrived 10 minutes later with dogs that sniffed through the whole hotel."
His room looked like "a hurricane had gone off".
The incident hiked the tension around a tour that prompted an unprecedented security operation in New Zealand.
For two and a half months, anti-tour protesters clashed violently with police and pro-tour protestors.
Razor wire strung around pitches to keep protesters in the stands led the South Africans to be dubbed the Barbed Wire Boks; specially formed police units called the Red Squad and Blue Squad protected the visitors.
Two games were cancelled: the scheduled second match of the tour against Waikato after protestors dropped nails, glass and tacks over Hamilton's Rugby Park; and the scheduled ninth game against South Canterbury in Timaru.
There were noisy all-night protests outside hotels where the Springboks were staying.
With the Springboks staying at Eden Park in the build-up to the series-deciding third test, trapdoors were built in the roof of the former South Stand, to allow a rapid getaway if their dressing rooms were overrun by protesters.
During the match, the pilot of a small plane buzzed Eden Park and dropped flour bombs. One hit All Black prop Gary Knight, leaving him prone on the playing surface.
Stofberg said the Springboks knew they would face anti-Apartheid protests well before they flew into New Zealand in July 1981; but never to the extent which split the nation.
"We were just a group of guys who came to New Zealand to play against the best in the world. We were definitely not prepared for what we came across."
The Springboks kicked off their tour with a 24-6 win over Poverty Bay in Gisborne. For much of the day the protests were peaceful.
That changed three days later in Hamilton. Violent clashes between the anti- and pro-tour movements broke out around Rugby Park well before the planned afternoon kick-off.
Then anti-tour protestors tore down a barrier fence, leading to a pitch invasion. After the match was cancelled, furious rugby fans beat anti-tour protestors outside the venue.
"Security, when we arrived there, it wasn't so bad," Stofberg recalled.
"After [Hamilton], the Red Squad became part of our security and it got a lot more serious."
Despite the increasing violence, there was never debate within the Bok camp on whether to cut short the tour.
Seeing barbed wire around the pitch proved "a motivation to play the game and do the best you can", he said.
"We wanted to play rugby, that is what we were there for. But to see what was happening, that was sad to see."
Stofberg made his test debut against the All Blacks in their 1976 tour of South Africa. Playing them in New Zealand had always been a dream.
As well as captaining the Boks at Lancaster Park, he started at No 7 in his side's 24-12 win in the second test at Athletic Park, Wellington.
He didn't feature in the decisive Eden Park test, won 25-22 by the All Blacks after converting a penalty kick controversially awarded by Welsh referee Clive Norling nine minutes into injury time.
A 1981 Springbok reunion is earmarked for Cape Town, to coincide with the scheduled British and Irish Lions tour of South Africa in the middle of the year,
Asked if Norling would be invited, Stofberg laughed and replied: "No, but I am sure that somebody will mention it.
"Everyone has their own way of looking at it. But it is sad that something like that can change the final outcome of the tour.
"For us, in the circumstances, if it was one test each and a drawn series, it would have been a reward for all of us for what we had been through."
Despite the violent protests outside, the stands were full for the Springboks' 1981 tour of New Zealand.
But crowd fervour was missing when the tourists played their final test before flying home - a 38-7 win over the USA watched by just 30 spectators.
That remained the world record for the smallest test match crowd until internationals in Europe were played behind closed tours during the Covid-19 pandemic.
Nevertheless, the South Africans were well-protected by heavily armed law enforcement officers, including the FBI.
In Stories from the Touchline, newly released in digital format, Theuns Stofberg opens up about how the team had been told anti-Apartheid protestors "were planning terrible things for us".
"We heard rumours about snipers around the fields, and we saw the FBI guys with shotguns in their hands. There was even a pistol under each policeman's arm and another in a holster attached to his ankle. There was probably a knife on his belt as well. We weren't scared, but we were very careful."
The second match of the three-game trip to America - against an Eastern All Stars selection - was moved after protests and legal action. While the match went ahead without drama, a pipe bomb was detonated outside the Eastern Rugby Union HQ.
A game of "cloak and dagger" dominated the build-up to the final match of the tour, the test against America in Glenville, New York.
Only the teams, law enforcement agencies, the New York governor and a small number of rugby officials were told the venue.
On match day, non-playing members of the Springbok squad boarded a decoy bus.
The playing squad left in three vans, first to a safe house and on to the venue.
"The three vehicles would drive for an hour and the police would make sure they weren't being followed," Stofberg wrote. "Then we would assemble at a private house and wait there for another hour before we left for the field.
"Everything was planned in minute detail like in an army movie starring Clint Eastwood. But it wasn't a movie, it was for real."
Les Bleus have now won three successive tests.