I know this is a bit of thread drift so I'm sorry....
The 406MHZ thing
AFAIK is not so much a case of less false activations of beacons than frequency clutter. Ie peoples toasters setting off the SARSATs. The other big benifit is 406 beacons are aircraft/person coded so each is associated with an owner who's info is on file and can be contacted rapidly to determine if it is an inadvertant activation. So you stil get the false activation but instead of sending a sea king you can phone the owner up... who then tells you his aircraft is in the hangar, end of search.
A good overview is at
this US mil link.
The other benefit is Location Accuracy
406 MHz ELT W/GPS
Accuracy – .05 nm
Search Area – .008 sq nm
Search Area reduced by a factor of 45!
121.5 MHz ELT
Accuracy – 12 nm
Search Area – 452 sq nm
406.0 MHz ELT
Accuracy – 2 nm
Search Area – 13 sq nm