Optimised Duty Free at Heathrow?

Attempting to check in at one of the world's most crowded/high-profile airports, how bizarre that having had shoes, belt, jacket, laptop, watch, aerosols, sharp instruments and all liquids removed and x-rayed, been virtually 'strip-searched' via a full body-scan sensitive enough to detect metal teeth-fillings, the passengers are then encouraged to buy (at a discount!) a couple of litres of highly inflammable liquid in glass (not plastic!) bottles, to be hand-stored for easy access under the seat in front, or in the overhead locker ("where they can possibly fall out and injure someone") and are then presented with a pair of flight-socks fine enough to fit through the neck of each bottle, allowing the passenger to spend the remainder of the flight, under cover of semi-darkness, quietly assembling and even deploying a couple of DIY Molotov cocktails…

( Alternatively, why not simply be issued with a receipt in Duty Free, for collection of purchases on arrival at the destination? )
Have a safe journey…..!