system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] How do civilians know if someone is a real hero or not?

If I walk up to an active situation dressed like Captain America and start ordering cops around, how would they know that I'm not the real Cap (assuming we look reasonably similar)?  Would it matter? Is this a form a Stolen Valor?
gpt
You'd better be a body builder/triathlete, because if you're not the fittest person they've ever seen the deception is going to be obvious.  Add to that the fact that Cap is a celebrity and most people would have seen him speak online or on television.  If your voice doesn't match, you're in trouble.

The crime will depend on which universe at what period, but *impersonating a Federal agent* will probably be applicable in most versions where he works for SHIELD or the Avengers.