The other issue with multiple beacons in the one location is that some of the newer beacons do not activate if they detect another beacon already going off in the near vicinty. It was a problem with the ETAP ditching a few years back, the pax had 121.5 beacons on their wrists which activated but were a weak signal. The crews beacons didnt transmit on 121.5 as they heard another signal already going on it so the searching aircraft is very bad visibility had difficulty locating the rafts.