I would make sure you understand the age requirements of your league. Unless the suspected overage players are STUDs I personally would not make a stink about it. Sometimes you get siblings and friends who want to play together and 8U in not worth getting worked up over....just my $0.02.
I agree that it is not something to get worked up over, and I have never personally protested even though I have had suspicions. The trophy just isn't that important to me... However, after my first year of coaching travel ball I attempted to avoid tournaments that didn't check rosters. I realize it is always possible to cheat no matter what rules you put in place, but even basic rules will eliminate some of the cheating.