Join Date: Jul 2007
Location: San Francisco/Sydney
Programs: UA 1K/MM, Hilton Diamond, Marriott Something, IHG Gold, Hertz PC, Avis PC
Posts: 8,156
Sorry, should have been clearer. I'm not referring to the barcode sticker. Look above it and you'll see a second black sticker in the clear part of the windscreen, pretty much right in the middle of the photo. This has no printing on it (on either side), and has a real thickness to it (more than 1/32" thick).
I don't know that it's RFID, but I can't see any other purpose for it.