That's a pretty weak approach and indicates how bad your fanbase is if you have to try to do that to keep opposing fans from attending.
Isn't going to work, IMHO. There are lots of 49er fans in SoCal already (many of which are volunteering to help NorCal folks get tickets), from my understanding there are apparently credit card safety features or 1-time purchases available that don't transmit your address or that you can assign a different address to, and it doesn't work on resale tickets (StubHub, etc.). So, there are apparently some workarounds if you really feel like blowing $600 minimum (nosebleeds) to attend the game.