As long as they do not ,after loading the coaster a tv screen drops down in front of me and plays a 30sec. commercial for CNN before my ride begins, then I do not have a problem with having ads in the park.
As stated earlier by several people, as long as it does not hamper my ability to enjoy the park and it makes money for the park let them sell space on anything they deem appropriate.
If you look back at SFOG the biggest ad I can remember is the "CHEVY show". It was a 2min commercial for Chevrolet. Did anyone complain about that back then? I know I did not care.