I do that too, I just say, "bicycle," as I am getting off the bus. The drivers seem to appreciate it (the father of a friend of mine was killed by a city bus, I pay attention).

I also use Wald folding baskets and have them unloaded and folded up before the bus arrives. For whatever reason those baskets fascinate people as I am folding them. As far as a folding bike, it is no use, the rules say that no bicycles, including folding bicycles are permitted in the bus. This is the main reason I am trying to find some precedent of a bicycle being declared a mobility device.

Due to some medical conditions I can not walk far, I can ride a bicycle just fine though. So yes, I am one of those people that annoys one of the previous posters who doesn't like people to use the racks to ride a short distance.