Sorry but you are wrong.

There are many sun pass only toll roads and every year there are more. We are snowbirds and have had a sun pass for three years. Its free, and many bridges and airport parking are included.

When you activate and register your SUNPASS, you will list any of the cars and license plates that will be using it. Then, if any of those cars goes through the toll area without the pass on-board, the system (either automatically or manually by an operator) matches the vehicle to your account, and debits the toll.

Assuming that NJ has the same system as FL, I'd be expecting the same type of notification. Damn those GPS gadgets!!! Left lane if you have a pass-right lane for cash.

That's good to know. One reason I haven't gotten Sunpass is I figured it would be in the wrong car when I needed it! Sort of like my umbrella!

we have the one you can move to other cars

It is also important to realize that with the Sunpass you get a discount on many of the tolls. It turns out to be pretty significant if you take the FL Turnpike from TV to Miami and back.

The $4.99 pass is not able to be used in more than one car. It's affixed to the windshield with a pretty strong glue. It warns you in the instructions that if you try to remove it for some reason it will become inoperative.
If it's going to be moved from one vehicle to another, obtain the more expensive one that's designed for multi-use.

Why not just get a transponder for each car and affix it to the windshield. Transponders are cost neutral, as you get the purchase price back in toll credits.

When living in Chicago, we had I-Pass transponders in all our cars, linked to one account. In fact, we still have the Chicago transponders and use them for our periodic trips up north...

Since the OP now has the info regarding the unpaid tolls, I would be curious to know where and what toll roads were involved. It might help clear up some of the misinformation on this thread. I'm sure if the OP were billed then there would have to be some supporting documentation as to the details of the violations such as which road, the time and date of the violation, etc. I use Sunpass frequently and I can tell you that there is no detail left to the imagination!! Includes: Road, date, time (to the second), lane number and toll charge. I think the only info not posted is the weather conditions at the time of the toll?? OP-please help us clairify this for you.

A number of state tollway systems are tied in with each other. For example we can use our IL transponders in IN, WV etc., etc. and vice versa.

It's too bad FL isn't in this system, it would make travel more convenient for a lot motorists from other states.

True, but since my other "car" is a golf cart and I don't plan on driving it on any highways, the $4.99 pass works great for me!

I got a bill along with a picture of my rear plate in the mail the other day for running a 75 cent toll and a $2.50 admin charge. I have a Sunpass. I've been using it a lot lately. I noticed a low balance warning as I went through the toll. My account is set up for automatic replenish. I called Sunpass and was told that my car wasn't registered with them and if it was the bill would would have gone directly to Sunpass. I know I registered my car when I purchased the stick on Sunpass but whatever. Sunpass took care of the admin fee and charged 75 cents to my account for the toll. I increased the replenish amount to avoid this in the future.

Missed a toll in Orlando on my way to TV last month. Thrifty is supposed to bill my credit card $25 -- but I haven't received the notice yet. Thrifty wanted $6.00 per day while I rented the car for a temporary Sunpass, but I declined as I was only going to use the tollway the 2 days I was in Orlando traveling to and from the airport. I was also told by Thrifty that all tolls in Florida will be unmanned by Jan. 1, 2013. Not great for the tourists...or TV wannabees flying in and out of Orlando.