I think the trading standards officers would take a dim view of declared prices not being honoured. Mistakes can be dealt with, but if it were a policy - they would take to court.

We still need to know how they will resolve latentcy. If only to keep the shoppers' custom.

BTW the legal definition of fraud is "obtaining money by deception". Deliberation is not the arbiter. Mistake is no mitigation. Lawyers would love a chance.............