Friendly game of hold'em?

What circumstances are you referring to? Over-aggressive opponents? Or players colluding? You haven't described anything that would lead me to assume they were colluding. And even if they were, I wouldn't worry about it. If you play better than them you'll still have the edge over them. And wondering about who might be cheating to gain a 2% advantage (it's not big whatever it is) kinda takes some of the fun out of it doesn't it? You don't play in those games to pay your bills, you go there to have fun and BS with your friends.