If I can offer - I was bow hunting elk with a couple friends in K country the past few days and when we slept at night, a buddy had brought an electric bear fence - never had to have it 'tested' by a bruin, but slept SOOOO well knowing how effective they are.
HIGHLY recommend if you are camping out there in bear country.
Check the video:
http://www.youtube.com/watch?v=Sv2G-aRDvyY