So the neon light switching power supply's label with serial number and manufacturer were pictured.[1] And it was UL certified but with no FCC label. Will the manufacturer get a fine if someone files a complain? I am curious.
Power supplies don't require FCC approval, just a declaration of conformity.
If a neon sign is generating RF over multiple bands, it may be the neon tube itself. If the tube has a loose connection, there's some arcing outside the tube, which generates broadband RF hash. Well-known problem for bands that play small venues.
[1]: http://www.arrl.org/images/view/News/Evanston%20RFI-2.jpg