Jamie's reply got in there before mine, but I'm leaving mine anyway.
Right now it seems like the purpose of the Alter Cup is to include as many of the country's top sailors as possible, no matter how they have to interpret the rules to make that happen.
If that is the goal, just say so.
So your class does NOT have to be a member of US Sailing?
Did or did not the Alter Cup Committee specifically ask the Hobie Class and Performance Catamarans to designate sailors for the Alter Cup?