I would think that they might charge you for tolls if they get a charge on their tag during the time you have the car rented. But, with toll by plate, the charge should not go to them.
So, where did you see info that says the Toll by plate doesn't work on 417 or 528? I haven't found that in what I've read so far. Sunpass itself definitely works on 528 and 417.
If someone goes through a toll without using a payment method, how do you think the toll gets charged? It's because they get your plate/tag, otherwise everyone would be running through.
I'm sure the rental company would have active accounts. The fact remains that Sunpass specifcally states that toll by plate can be used with leases or rentals, but I haven't seen an exclusion for 528 and 417. So, please, point me to that information. I do like to be informed when I am a customer of the service. Plus I haven't been in Florida in almost 2 years so things may have changed.