Not exactly a security flaw, but eldest (and others) got so fed up with a school 'mate' inflicting his choice in music to everyone on the bus by bringing a BT speaker with him every day that he took to scanning for the device as soon as said eejit was on board, pairing his phone as soon as possible and playing such classics as Abba, Fleetwood Mack and the theme from Thomas the Tank Engine.
Apparently this worked for quite some time (weeks) before aforementioned twit worked out the only way to stop it was to switch the speaker off, but of course switching it on again meant a race to see who would connect first :-)
M.
Biting the hand that feeds IT
