Eric hits some important points here (others have also mentioned this).

Putting the non-spin boats into this discussion is ultimately a red herring. True, some of those sailors may not appreciate the exit strategy for a spin boat, but that does not really matter. A spin boat going upwind is going to have the same difficulty getting out of the the way of a boat that isn't in control.

In the interest of safety, perhaps we should have some discussion at mixed-class regattas to let everyone be aware of the "limitations" of spin boats (can't hurt). Of course, you are still obliged not to change course without giving the other boat the ability to keep clear. Which means, you're opening yourself up to a larger window in which an upwind boat can say in a hearing, "Hey, spin dude never saw me, so I needed to give him extra room in case he got hit by a puff. I started avoiding well before he could hear my hail, DSQ him now please."

Mike