The sensors are not unique to BMW - as long as the fitter is aware of them and knows how to deal with them there should be no problem.
Having said that, the tyre can easily have a mind of its own even though the fitter is careful/knows the correct procedure. Even at a BMW workshop, if the tyre pops off the rim awkwardly the bead can catch the (flimsy, plastic) sensor and snap it off. At a BMW shop they'll hopefully have new sensors in stock and can simply pop a new one in (and recode the computer). At a non-BMW garage they'll just put a normal valve in temporarily and you'll have to go back at a later date when they've obtained one. If you've got a GS-911 you can recode the computer yourself, otherwise it's a trip to the BMW shop.