I see guys cheating all the time, grounding clubs, foot wedges, mulligans, but as long as I keep my score honestly, I don't really care. I am trying to get better for me, not to impress anyone else. Now if it were in a tournament, then yes everyone should speak up for the good of the game at the very least. If it's not a serious match then I try to have as much fun as possible and not concern myself with what anyone else is doing.