I think Cain's stupid tattoo is stupid. He's a great fighter, and a greatly humble competitor, though. It's impossible to dislike him if you have brain cells.
With that being said, most of the Marine Corps moto-tats are stupid, too. You've got your standard Old English "USMC" on your left tricep, or your motivated EGA over your breast. That is, until you get out of the Marine Corps--and whether or not you hated every second in the institution... you're bound to think it'll impress people by getting one.
Hey, BTW. Andre Galvao was spotted at TUF 13 Tryouts--apparently he got dropped from Strikeforce after getting handled by Woodley. That shit is gonna be sweeeeet. If he got in a good year or two of serious striking/wrestling practice, he'd be out of control.