There may be more on how the sensor works out there now but it was proprietary "magic" when these things first came out. It does seem to be able to figure out the difference between a hot dog and a wet stick but one of the guys who had them said he did have a false trigger.
I am not following rec.woodworking these days but it should be easy to get a thread started if there is not one on there now. Guys are passionate for or against these things. It is sort of like 4 stroke outboards vs Etec or "classified breakers". Easy to start a fight.
