The heat and the stinky hitchhikers obey simple laws of physics and tend to follow the path of least resistance. The path of least resistance is not through the garment and into the many pores and channels contained in the AC. The path of least resistance is to go around the garment, through major openings such as your belt line, your collar and sleeves, or through the opening of your facemask. This is called the “chimney effect.”
Like smoke rising from a chimney in your home, most of the stinky gasses bypass the garment and expel through the opening of the collar
In other words, don't have beans and chili for dinner the evening before you go hunting.
Just who does this guy think he is, anyway? Trying to confuse the issue with facts...
Really, the guys that believe in the stuff are not going to be swayed. Others will pay the price just on the slim chance that the stuff MIGHT work. A whole lot more will buy the stuff simply because it's on the rack.