--have the potential to help somebody, at some time, with some condition. Our bodies are so complicated that if someone says that a certain treatment/device/regimen cannot help anyone, that someone is most likely incorrect.

And, of course, many things accepted as mainstream treatments today started out as "crackpot ideas". A number of formerly "crackpot ideas" are in the process of becoming more mainstream--what this takes it time, good reports, and most importantly, good double blind studies that show benefit.

THAT is probably the best question to ask at these fairs--"Do you have any peer-reviewed articles/papers involving blinded studies that show a benefit to these things over placebo?" The reaction of people to that question may tell you all you need to know for now.