I think you can force a TV event to occur by beating the elite 4 and waiting until midnight in-game. Its worked the past 3 times on my emerald game but it might be a glorious coincidence and I haven't seen any discussion on it anywhere so could someone(s) who still has a gen III game try this out and report back?

Which TV events? I don't think there was anything other than the Clearance Sale and Swarms. The sale event doesn't become available until after you beat the E4, although it is supposed to be random and infrequent. I haven't heard of beating the E4 in order to trigger the event the next day.

Currently I only have 2 badges in Emerald so I can't check right now. I'll get back to you in a week maybe, unless somebody else does so first.

There's also the blend master and I get the feeling there's something else.
EDIT: The something else is that the guy who sells drugs in the slateport market has a 50% discount on all items.
EDIT: And the game corner special event. I can't remember what happens but there's a TV event involving it.

Swarms, Rooftop sales, the game corner, Vitamin Discounts, the blend master, interviews, nicknames, and if you mixed records, interviews and story things from others.