I believe what you are doing is an "argument from ignorance", basically stating that it is true because it hasn't been proven false.
Since "Bone Conditioning" is a commonly practiced, traditional, and widely believed in form of training, shouldn't it be the skeptics job to prove that it DOESN'T work and not vice versa? I mean I don't practice the crap myself, but Galileo didn't tell anybody, "The world isn't flat until somebody proves to ME otherwise!" Since you're trying to get a point across to a larger group than yourself, that being the TMA guys who actually do practice it here, you should be the one doing some research or looking for scientific evidence to back up your view, not the one sitting around with a slurpee waiting to be convinced. Too many people have already done plenty of studying and claimed that science is on their side who will argue that this kind of conditioning really does work.
So even though I'm with you, and don't believe in conditioning the bones by hitting trees or any BS like that, when it comes down to actually working to try to prove something does or doesn't work, the score reads: TREEHITTERS - 1, YOU - 0.