re: What’s up with the windshield wiper condom they put on the back of SUVs?

I think they're so the machine brushes don't get caught on them and either pull your wiper or pull the brushes out. Avoid's damage to your car and/or the machine's equipment. (Avoiding damage liability) ;-)
At some wash's, the attendant's tape the wiper down to your back window. I hate the tape personally, but I understand the risk.