Here's a little something I found...
Note that the brush I was using was plastic and very worn. As was the brush that my wife's co-worker was using and the same in this video.
I've switched to using the wooden Weber brushes and have not had a problem with losing bristles since...
Shawn aka: BUBBA's QUE CREW Competition Team
Blue Weber Performer w/SS top & gas assist
Weber One Touch Gold & a Weber 22 1/2" Silver
2 UDS's Born 9-19-08 & 3-6-09
Weber Smokey Joe Platinum
Super Fast RED THERMAPEN
"If you got them by the MOINK balls, their hearts and minds will follow" -John Wayne