Interesting that you should bring that up, Eric, because I have been wondering for years why ISAF does not crack down on the iceboaters for holding world events and does not penalize the sailors by banning them from sailing in ISAF-sanctioned events on soft water.
Many landyachters and possible iceyachters as well as organised in their own association called FISLY.
At the end of the day ISAF will not pick a fight with a rival organisation of similar international standing.
I think FISLY is even older then ISAF and therefor they will be laughed out of the room if they ever tried anything like that. Also ISAF is not at all interested in landyachts and iceyachts, they are interested in "old boys" monohulls.
Note how the moth class (monohull ?) is having problems with ISAF as well. I'm sure many skiff classes are on a pretty uneven foot with ISAF as well.
Personally I see a good potential for setting up a rival sailing class that encloses all the performance sailboats and sail / kite boards, leaving the archaic monohulls and ocean racers to ISAF. As far as I'm concerned ISAF can have those and continue to live on as a mono ocean racer club.
Wouter