A slight correction. New Jersey (and Oregon, the other state), do not require full service. They only prohibit self-service.

Full service, at a minimum, includes pumping your gas and washing your window. In some places it can even mean checking your oil.

I think you will find that 99% of all gas stations in Jersey and Oregon do nothing more than pump your gas. In other words, it is not full service. It is simply a ban on self-service. A lot of stations in Oregon refer to it as "mini-serve".