First of all, that's not a deterrent, though. If I can steal your money and all I have to do is return it if you catch me, I'll keep doing it. So you need some sort of punishment on top.
Which brings us to the second point... At minimum you should be fined, at least to cover interest gained while you held the money, probably more to cover emotional distress and otherwise.
Plus, at those kinds of sums, we're somewhere into "stole pension money territory" where we're only a few minutes away from "old lady took her own life after losing life savings".
So things are a lot murkier than they might seem.
