I have worn hearing aids over 30 years and also have had the unsettling
experience of picking up Transmissions in airports and certain "secured"
buildings ... more so when I have worn BTE's with a T-coil or a
programmable. One theory proposed was the oscillations of the security
system is what my circuits were picking up. Sometimes fluorescent light can
be an interference. Generally I haven't had too much trouble with the
magnetic security systems though on occassion they do react. On the whole
I haven't worried about it, and take notes when my clients report it
happening to them and where.
Sandra Hobson