To be honest, I can't say her going to every show annoys me. If seeing a band is your ultimate happy in life, go for it, go see them as much as you can. I would love to be able to have the time off work or the money to do that.
What DOES bother me, however, is her staying in the same hotel as them every night of the tour. Hanging around the lobby for a photo for the 8th night in a row. They arrive at the next city, check into the hotel, and who's there in the lobby? They check out, drive 2/3 hours to the next city and they arrive at the hotel and who's already there checked in waiting for a photo? Yep, you guessed it.
I think doing it once could be forgiven, even though that's their private time, you can forgive it once. Not every single night of the tour, that enters into invasive (insert a number of other words) behaviour.