Ever heard of Kpfa Berkley they have a staff of marketing sales people to get their underwriters as well as many NPR affiliates last time I checked that was not illlegal .. go figure they have bills to pay!!
You picked a mighty poor example. KPFA is an example of bizarre management and inability to sustain its operation.
At non-commercial stations, those who seek underwriting and donations are called "fundraisers" and not marketers or sellers.