It won't cost them much. I'd write them a letter stating 'The chances of this being a success are so remote and, in any case, will only lead to years of strife with both your remaining employees and with most of the sentient population if they retain a choice of shopping destinations, just ditch it now and do us all a favour. Please reimburse me for the postage stamp used.'
Just been reading today's Sunday Times. An article in the magazine by a young, trendy male whose name was Matt something (isn't it always?) which started with his experience of The Queue which quickly became obvious was about his experience at his local Sainsbury's self-scan tills, made much worse since the human tills were halved recently. In fact, because of 'technological issues', only one was in use. He quite rightly analysed the reason why it can take so much longer to use self-service, even if you don't need to wait for an employee to verify your age at some stage, and even if there's sufficient space to deal with a trolley full of shopping. As he says, once you've scanned something it has to meet what he called the 'paranoid Android' test i.e. the scales have to agree that any suspicion you're trying to defraud them hasn't happened on this occasion, and this adds precious seconds with every item before you continue. He's now going to Aldi for his shopping. Then Rod Little, always worth reading imo, with his take on such things. The worm is turning.