Some online asked if the retail registers do anything different if you have a 'suspicious combination' of items. The general consensus was no, but I shared the following experience that led me to believe otherwise. In 2005, I tried to buy two small jugs of denatured alcohol at the Cottage Grove, OR Wal-Mart for my flamecannon (started as a pneumatic spud gun but then when I found out it would turn liquid into an aerosol mist, I put a torch at the end and started shooting 40' fireballs and mushroom clouds instead) and the system would only allow the cashier to ring up one because of whatever else I was buying along with it. "What? Why?" I asked, probably in more words. "Computer thinks you might be making meth, dude" is roughly what the response was. They couldn't override it and I had an insufficient amount of denatured alcohol to get my flame on but what could I do? Later that evening after we almost immediately ran out of denatured alcohol from my one tiny jug, my brother-in-law asked if I thought acetone was flammable because he "has that". "Sure", I allowed, "I believe it is". We poured some down the barrel, lit the igniter torch at the end, and fired it into the air. Now with the alcohol, the aerosol would punch through the flame and be slowly and majestically lit from behind as the flame 'caught up'. End result, a low "boom", a big fireball that climbed into the sky, and a fine mist of whatever alcohol didn't 'catch'. With acetone, there was a measurable difference. First, there was no unused acetone. It ALL ignited. Second, it ALL ignited i a roughly 2-3" sphere of pure energy at the very tip of the barrel where the flame was. It was one of the brightest things I've ever seen, and to this day, if I squint my eyes, I can just barely make out the outline of the barrel to my long-departed flame cannon with a round cutout at the end. So yeah, I think there is some amount of computermization of things people purchase.