mrbb...I hear what you're saying. But I also know the deer around here. Any, and I mean, any indication of a human around they go ballistic. I hunt exclusively public land. This buck I shot is at least 3 years old so he's been around long enough to note human danger when he sees it and there was no way he could have not seen me moving around.
Like you said confidence is a big thing. I'm not 1000% sure it works but there has to be something to it. I'll keep using it though and relate my own experience with it.