For an example of how that plays out with a malicious corporation, look up how much Fed Ex and UPS pay in parking fines/tickets in NYC.

Urban myth is that a previous version of the ticket paperwork required that the vehicle manufacturer be accurately filled in, and this was one of the reasons for UPS trucks being so plain/unmarked, and since that could not be derived from the (lack of) badging or the registration paperwork (which version for trucks did not have the matching entry requirement), UPS didn't have to pay tickets while other services did.

UPS trucks are custom-built for UPS, and they are destroyed at EOL, not sold off. So, safe to assume any UPS truck you see is owned and operated by UPS.