In my experience with cats, people generally follow the rules. If someone shows up with a modification at an open class event, they tend to be fully up-front about it.

The only equipment issues (including some protests) that I recall seeing have been regarding boat/crew corrector weights (and needing to keep the corrector weights on the boat for the entire event), and the infamous centerboard line length for the H17. There was also the issue with the mast cap at a H16 event in South America (new style cap on non-comptip mast).

Then there was the guy who removed his Hot Stick and started swinging it at a fellow competitor on the water in a drifter, but that was a different issue (and 69 hearing) altogether...

Mike