Today’s airplane bombing plot, supposedly involving mixing chemicals on board a plane, resulted in the banning of all sorts of liquids and semi-liquid substances in carry-on bags. If this possibility is real, the threat could last. So what’s the permanently mandated security measure? No carry-ons? No bottles of shampoo or soda or perfume, no tubes of hair gel or toothpaste, no cans of hair spray or deodorant? Maybe new products will arise like dehydrated versions of many these products, packed in little foil pouches. Maybe teeny travel versions of these products will be deemed safe. Maybe overhead compartments will lock all carry-ons in. (Good luck policing that.) Still, one wonders if something the size of a toothpaste tube could be lethal whether any measures could work. Some experts are even calling for a ban on all batteries, which could be used to trigger plane-assembled devices. Not looking forward to the day when reliable mind-reading and lie-detecting machines are finally invented and are used to screen all passengers.