Yeah, I think he used it as an expression rather than a literal punishment. I think he even spoke to that at one point, how truly horrifying it was. I wish I remembered the passage better.

The point of it was, his ideal citizens in his ideal world were all wise and righteous and so forth and so their punishments would truly fit the crime, in a harsh and 'ideal' way. Someone who cut in line might be thoroughly, publicly embarrassed or whatever. Someone who assaulted someone else or threatened others lives through carelessness might be banished or killed with no one wasting a moment's tears over it. Because of course it's simply unacceptable, in a polite society, to not consider the results of your actions or to put someone else's life in danger as a result of your own greed, right?

Yeah... that's why I said it's a fond fantasy. It would be nice to live in a society where it was unthinkable to cut in line or drive drunk. Meanwhile, what has our society actually devolved to? Someone feels aggrieved and so of course it's acceptable to drive a car into a crowd of strangers. We're not even close.