"Equally, we'll look to them, through their own channels and own networks, to manage what they're doing for themselves."
The original Lions contract sent out to the players ahead of last month's squad announcement contained a clause prohibiting players from using any form of social media during any of the tour's 10 matches during a "specified period of time prior to the kick-off of a match and after the conclusion of a match, to be advised by the tour head of communications".
However, it quickly emerged that clause, already used by some clubs and national sides to cover the 36 hours before and after a match, would be invoked only in extreme circumstances unless the players themselves under captain Sam Warburton decided otherwise.
The 41-man squad have since received a "social media pack" including guidelines about not publishing any sensitive squad information, such as injuries, before they are publicly announced, or making negative comments about opposition players, coaches or match officials.
"We will educate the guys on what those guidelines will look like but it's up to them to determine what they actually are," said McEwen, who declared the same applied to any drinking policy.
"Going out for a beer is a great way to break down barriers. You've got four completely different cultures coming together in one jersey to represent the Lions and it's important that they set their own guidelines."
McEwen also confirmed securing more preparation time for future tours was the Lions' top priority during upcoming negotiations over their next three trips.
The squad play their first match in New Zealand days after the Premiership and Pro 12 finals and head coach Warren Gatland wants that to change from 2021.
Echoing the Kiwi, McEwen said: "The most important thing is preparation, preparation, preparation.
"And that is time the team have together in the UK and Ireland before we go to New Zealand, South Africa or Australia."
He added: "No professional sports team would put themselves through that impossible task within a week.
"So, preparation is what we need. Time is what we need."
Legendary Lions coach Sir Ian McGeechan concurred, saying: "Give them the time because the product at the end is so good for the sport that you cannot afford to get it wrong.
"It's more than just a Test series.
"It is the respect for the uniqueness that this team has, this jersey has, that, I think, if we can hold on to, we've got something that remains hugely powerful within our sport."
Despite the intense schedule, McEwen said the Lions would not curtail the squad's community activities while on tour, citing the importance of a visit to the Waitangi Treaty Grounds, where Maori chiefs first signed an accord with the British Government.
McGeechan claimed that was one area where organisers of the last tour to New Zealand went "wrong".
"It was one of the things we got really right in '97, 2009, I think, where we purposely went out," he added.
"And it was a joint effort between sponsor, players, management to say, 'This is it'."
