Originally Posted by
everDraed
I've had some cars in which the toll transponder is attached to the windshield in a (lockable) (closeable) metal box, but the majority of the cars I get are registered in the licence-plate based systems. Secondary charges generally don't appear as it seems that the plate lookup and charge system is only triggered if there's no toll payment via transponder. I do keep my records and on two occasions have used them to have the extraneous "convenience fee" removed.
I still have that Sunpass and have since added a portable EZ-Pass transponder to my go-bag. Most of my driving travel is along the east coast - Sunpass works from Florida through the Carolinas, EZPass for all points north.
Same experience here. I was in Florida a couple of months ago and both cars (with Hertz) I had while I was there did not have any transponders installed, despite having Florida plates. I bought one of the sticker tags for $5 and it actually worked fine just firmly holding it up to the windshield through the toll gantries--my experience, at least, is that you don't need to peel it off and permanently stick it, though most people do recommend getting the portable transponder (for $20) if you plan to use it in rental cars.
Cars in the Northeast usually have the lead-lined flip-open cases that you can shut if you want to use your own transponder (or pay cash).