On the Golden Gate Bridge, they snap a photo of the back of your car, then using the license plate number mail you an invoice. It is really slick and actually works well.
I don’t know if California DMV works,with other state DMVs to mail invoices to out-of-state tourists.
I used to rail against toll transponders, but now figure that there are massive license plate scanning databases extant. There’s no escaping being tracked these days.
What does bug me is that the transponders were specifically designed to omit feedback - i.e. beep or something when you get charged.