My point (and Plato's) was rather that some people will definitely cheat, because it's locally rational, and it's actually better for everyone if they are "classy" about it and don't flaunt it too much. A minority will get away with terrible things, but somewhat bounded by conspicuousness, and at least the majority remains blissfully (willfully?) unaware and propping up the civilized system which is so much better for all of us.
It is quite a cynical point of view of course. It's a hard balance, when it gets bad sometimes it's better to air the dirty laundry and go through the pain of purging those cheaters.
But the worse thing is to have people be loud and proud cheaters, which is happening more and more. That's a deadly virus to a civilized society, everyone starts thinking they are dumb for not cheating, and we quickly go back to the dark ages.
It's a bit like calling out the bank for being a fraud because they don't have all the money in a vault, and rushing to get your cash out. If people start taking the red pill and shouting that society is just a game of pretend, which it kind of is, then our very real prosperity can vanish overnight.