You know I think too often we dismiss something as quackery or whoever is pitching the idea as being some charlaton because it's lack of evidence.
One of my teachers one said absense of evidence does not imply evidence of absense and I think that is probably the case here.
My re-cert last year we were told to do the heimlich however, we do not have a formal procedure for choking but from what I understand the "absense of evidence/ risk of potential harm" line is being touted as a reason to not do it.
I have used it several times to good effect and have no plans to stop honestly; look at it this way, we're taught the best thing a choking person can do is cough .... you look at the mechanisim of action of coughing vs the heimlich .... don't seem that far apart to me!
While anedcotal at best, I haven't seen very good results with back slaps, seems almost like a waste of time if you ask me.
.... where is Intensive Care with them fancy forceps when you need them?