I think the definition you have is good, except I would say “proposes to pay for media” instead of “pays for media”, because it would make items reviewable if governments gave a donation to community groups or organizations that, then, subsidized an event and it resulted in an advertisement.
I would also include householders. We haven't talked about householders. Bulk mail is now, as I understand it, excluded from their definition of advertising, and that's a problem as well. That's a big loophole. That's not a definition, but—