For what it's worth they DO check the weight of the boats in Australian championship events. When I went down there for the 2004/2005 H-18 Worlds, they weighed in every boat as well as the skipper/crews. It was obvious this was not the first time they had done a weigh in, because the Aussies had some very cool ways of adding weight to underweight boats, or for making up for underweight skipper/crews.
Stephen
H-18
The weight of the skipper and crew has always been checked so it meets the minimum weight on every major Hobie 16 regatta I've sailed, but never the weight of the boat.
During the Europeans they sometimes check the top boats skipper+crew weight after a days hard sailing and you must still be above min weight.
/hakan