Those dealers are wrong...although they are passing on BRP's standard advice. I am not saying that the problem is not common on Spyders, but that does not make it "normal" or right. It does not have to be that way! My tires have 25K on them right now and are barely over half worn to the wear indicators. They are worn evenly. Nancy has 7K on her GS and the tires are even and have over 3/4 of the tread left. An alignment to the latter spec for the 2008-2012 Spyders would do you good. Rotation is futile...it merely swaps the improper wear to the other side of each tire, and buys you some time before replacement. Many times the Spyder tires won't balance well after the rotation, and then they wobble and vibrate. In addition, rotation requires dismounting and remounting the tires, then rebalancing them, so you will spend at least half as much as the alignment would cost. You can't save the tires you already have, but it would pay for you to have the Spyder realigned to the tight side of the proper spec, then install new tires.
Thanks again. I think I will just run these into the ground, then go to a different dealer, get the alignment and new tires. I agree that rotation is a waste of time and money, and could create other problems. At least the tires aren't very spendy. That helps. It's hard to put a price tag on good fun.