I found this mildly annoying. I was rating my friends short film (btw watch it) and I would actually like to hear more about the competition, but my only options are hear nothing or hear everything. Why can I not hear more about Virgin Media Shorts without being bombarded with crap from Virgin Media (which I can't even get) and Virgin Mobile (which I don't even want)? Surely the whole point of doing stuff like this is (or should be) to make people warm towards your brand? A soft-sell if you like. Not just a way to build a database for mailings about mobile offers.
And anyway, it's not like you couldn't advertise to the 'Shorts info only' people. I'm sure you're allowed to put adverts within emails that are about the thing they've signed up to.
I know I need to stop ranting, but brands need to stop being annoying first.