in the few years of catsailing i have been doing, nothing compares to the aggressiveness of monoslug sailors as far as rules go. Was racing the flying scot this weekend, rouned A in 2nd place as the wind was dying. the boat behind caught a small puff and came down and below us, came up about 4 bootlenghts to start drifting just us and tap us. That is headhunting, legal but bull **** was to act.
At least here in the US I do not see that out of catsailors in the level I sail in.