Will game stop track me down? Or will the police come and find me?

So I was at a wrestling tournament and when the matches started I was working concessions when I noticed something on the stairs I went up to it and it was an iPhone. I waited for someone to come back but no one did After the tournament I went to GameStop and sold it. If they deactivate the phone will GameStop or the police pursue me?

How do I rob someone?

So I was thinking selling my iPhone to a guy in cash, and when he pulls up we hold him at gunpoint and take his money. Is this smart or bad idea? And I'm talking can I get caught this way. I'm doing it where there's no cameras either, and there's no cameras on my way home. I'm gonna use clothes I never use and a mask.