Remember that MLB.tv is also blackout free for you overseas.
What about on a military base that is domestic? I am leaving Tuesday for Camp Geiger, NC and will be there for the next 1.5 months or so.
It would have to go through DOD servers, so I would think maybe they have a proxy system that MLB.tv recognizes as military and won't black out.
But I am not too sure on that.
Edit: Come to think of it, it doesn't even really matter because I doubt Jacksonville, NC is in the blackout region for the Marlins :lol .
Biggest issues in NC are O's/Nats blackouts so you have to watch them on MASN.
Although I believe that the bases each have zip codes set aside for them, so MLB.tv may not include them to blackout.