I've spoken to the electro physiologist and the Medtronic rep. Neither really didn't know but offered the same general advise- keep a reasonable distance. The alarm also activates when the battery is nearing end of life. I heard it last year.
Funny thing- I'm a litigation attorney and not long ago I deposed a fellow who claimed that his need for an AICD was because of an accident (BS) and then he listed a laundry list of things he claimed he could not do because he had an AICD most of which are nonesense (he can't operate a tv remote, he can't drive an SUV are 2 of his claims). After giving perhaps a half hour of perjurious testimony, I took out my Medtronic ID card and asked if he had one like it. Well, once he and his counsel realized they were piling on a load of crap to someone with first hand knowledge, the cardiac claims vanished. His AICD was real, just not accident related.