Then, after lawmakers endorsed the amendments last week, the Government called a snap referendum, preventing any remaining opposition to prepare. More than a week before the vote, Sissi's supporters plastered Cairo and other cities with banners emblazoned with his face urging Egyptians to vote "yes" for the changes. On dozens of rides around the capital, not a single "no" banner was visible.
This was not the first time Sissi has gone all out to retain control. He was re-elected last year after all his credible opponents were pushed out of the race, including through arrests and other forms of intimidation.
With the constitutional amendments all but certain to pass - results are expected in a week - the Government is hoping for high voter turnout to create a veneer of legitimacy for Sissi's tightening grip on the Arab world's most populous country.
The National Council for Human Rights, a state-appointed group, also reported voters receiving food in exchange for votes. On social media, videos circulated of voters taking cartons of food if they voted "yes" on the amendments. There were also reports on social media of votes being bought with small amounts of cash in poorer areas.
In a statement, the government's State Information Service described reports of food handouts as limited and that no state entity was involved. It also said that if the Government wanted to influence voters, it wouldn't need to resort to such measures.
The National Council also reported that vehicles emblazoned with signs of political parties were spotted transporting people to polling centres.
Trucks drove through the streets of Cairo with LED screens on their sides playing videos promoting Sissi and urging people to vote.
Some voters said they were ordered by their superiors to vote for Sissi.
"Our principal dictated to us what to do," said Menna Ahmad, 34, a science teacher who said she voted "yes".
"She told us, 'Go. I support Sissi, and you have to support him like me.' She actually told us to participate, but practically speaking she forced us to support Sissi and vote 'yes.' "
Ahmad said she was also told to take a photograph from inside the voting centre to prove to the principal that she had voted.
Voter turnout was under 40 per cent at some polling stations. In some cases only about 25 per cent of the registered voters had turned up over the past three days, election monitors said.
"A lot of people are opposed the amendments, so they are not coming," said Wael Seif, the chief monitor at a voting station in central Cairo. "Others are clueless. They don't know their rights. Of course, one wishes everyone will participate, whether they say 'yes' or 'no.' "
Most Egyptians said they voted to prolong Sissi's rule. Some said Sissi would bring political and economic stability, while others said it was essential he remained to combat terrorism, especially a virulent Isis (Islamic State) branch in the country's northern Sinai region.