That's actually a great idea, but I'm guessing your average stoner would rather spend the money on weed than test kits, thus reducing the motivation to test much of anything, except possibly inhalation techniques.

When I was first trying to brush back up on weed last year when my sister was sick and we were trying to find cannabis-based help, I remember being fascinated by one of the seed sites, which told approximately what the THC levels were in its various strain offerings. We rarely knew what strain it was in my college days, much less its THC percentages.