That is correct, they will only work in the stadium. They will work during road games in their stadium as well.
I was thinking about purchasing one but then I remembered that I can't stand listening to Dave Lee doing play by play.
I got one, as did someone else in our group, and we commented how nice they were to have. It was great to get the information real-time at the game, without delay. Also, the fact that they will work at the road games will be a big plus. In my opinion, it was well worth the $15 bucks we paid for them...also, I'm assuming they will be used for Gopher basketball as well.