I can say that I have never come across cheating in cat sailing, but more of a misunderstanding of the rules.

However, there is one exception where it was blatant felony of the rules. The situation in question had to do with a race where one of the racers didn't round one of the marks (a huge oil rig). After the race, and before the awards presentation I approached the skipper had asked them if they knew what the course was etc.. only to make things fair before we protested. Needless to say, they "thought" the course was..... and it was at that time we (and few other jumped in) had asked them to disqualify themselves which they didn't. And this is where it gets better; when we approached the race committee, they had informed us we were wrong as the course for our fleet was shortened to the buoy a 1/4 mile in front of the rig and we didn't have to round it per the race instructions. They then in a very flippant manner and told us we should have paid attention at the skippers meeting. At first I thought I had attended on Greatful Dead concert too many in my youth as I didn't recall hearing the amendment. However, four other participants who saw the infraction; with two not having a vested interest as they had to go around the rig, had also agreed that this was not articulated at the meeting and the understanding was all had to take the last mark the oil ring to port..... Needless to say this fell on deaf ears as the race committee stood by the initial race results and was certain about the amended instructions. At the awards presentation there were some strong accusations made about the skipper of the winning boat, his relation with the promoter of the race with something about having carnal knowledge of each other which almost evolved in to some physical confrontation - so I was told as I was already packed up and gone.

They way I look at it, when it comes to cheating, the only person your cheating is yourself. In some cases like the above mentioned yes it is a felony, in other instances it may be a case of not understanding the rules. If the latter, try and the help the person out.