Those that have passed with magic potions did so because of the dilution factor associated with the products use and not the product itself. All magic potions work via the principle of dilution (that is, when they do work). They work because of the amount of water thats required to be consumed with them. When people pass, they wrongly credit the magic potion when the real hero was the water consumed with the potion, which effectively diluted the concentration of THC metabolites in the bladder to the point where the sample registered below the screens cutoff limit.

Its all about the water.