After the furore last year when it turned out that UK airport shops were demanding boarding passes to save themselves VAT but not save you any money I assumed that this was the effective end of the weasel. From my recent experience at Birmingham International (motto: "We put the 'slack jaw' in 'security'") it seems not.
First stop: the bookshop, to buy some doorstop-sized illiterate literature. No shortage of supply. I present the volume to the lady at the till who demands: "Boarding pass?" with no hint of shame. I enquire whether it's actually mandatory, at which point she rings up the transaction with no further questions. 1-0.
Next stop: W H Smith, for a magazine. Avoiding the single human-manned till I opt for the self-service till. I scan the magazine for a grand total of £2.50 - and it asks for a boarding pass, and won't proceed until I scan one. I hit the "my boarding pass won't scan" button, wait a minute for the roaming attendant to punch the override and proceed on my way. But hell, I remember the huge fuss in August 2015 about this. It seems that the airport shops were content to let the hubbub die down, then go back to their old ways.
Don't let them do this! Make them pay a cost in salaried worker time for each time they demand a boarding pass. Once the average worker salary rate times delay is more than the expected VAT, they will shut up about the boarding passes and let us buy our dubious literature un-monitored and without delay. (Until 1-2 years later when some bright MBA spark spots an opportunity to re-introduce the practice, at which point we hang them from the Heathrow radar pillar as a warning to others.)