1. Kind of depends. If the recruit isn't there on an official visit, then it is a violation to buy him anything. Is it cheating? It can be because it's providing an impermissible benefit. Now, if it was enough to get the recruit to sign...I'd hope it was a really, really good cheeseburger. lol
2. Yeah, that's cheating...the 50,000 in the stands can't even see the signs without binoculars and they don't show much of teams signaling in plays on tv. So, if there were people there trying to decode another teams' signals on Michigan's behalf...yes, that is cheating.