New Yorkers, at least, do this deliberately to show off.

In many years there I saw quite a lot of eyepopping balances there, just about as many perfectly regular or small balances.

And I'm sorry, but having six figures in your checking account puts you in a small a minority, even in Manhattan.

It wasn't random. It's a brag and also a way of disheartening the proles. "Someone else will feel inferior to me!"