Obviously this situation in Belarus is a simple legal restriction and not a wall, but I’ve long thought that a sensible constitutional guarantee would be the right to leave the country at any time.
In totalitarian regimes, constitutions aren't worth the pixels they are printed on. Rights guaranteed by laws must be enforced by the judiciary and the executive. But that only happens if (1) cases actually reach a court, (2) that court is independent, and (3) the executive is willing to enforce the court's decisions.
Indeed, according to https://en.m.wikipedia.org/wiki/Constitution_of_Belarus, "Citizens [...] have the right to protest against the government." Problem solved?
Borders with Lithuania, Russia and Ukraine are a bit more leaky, but one has to be physically fit and logistically prepared to cross, and there is still a risk of being caught. And then what about kids and elders?
So, this is not a legal restriction, but a real ban.
Interesting, it mostly runs along arbitrary forest paths etc, not major rivers or mountain ranges - not naturally easy to police.
I once stayed in a cottage in the Bialowieza forest (one of few bits of primeval forest in Europe). The cottage was at a clearing, and the other side of the clearing was in Belarus.
We never got any trouble for it, but it wasn’t rare to have border patrol appear out of nowhere and kindly enquire what you’re doing.
These days Lukashenko is very unpopular in the country. He falsified elections, his people committed a lot of violence against the innocent. He is putting people in prison, denied the entrance to Belarus for the citizens. It is a very bad time for the country now - many people and businesses are leaving the country for Lithuania, Poland, etc.
He did not do any economical reforms either, and most state companies are almost dead and cannot compete on the market. He totally relies on donations from Russia. Thanks to him Belarus is not attractive to investors. IT businesses, his golden goose, are leaving.