Never had a problem in Tesco. I very rarely use supermarkets as I feel that they are very unethical suppliers. When I do I pick areas where I know I can get away with being barefoot. ie Selly oak which is a uni student area or Moseley which is very bohemian and anything goes..I. doubt if I could get away with it in other parts of the city! sainsbury's and Aldi seem pretty laid back and don't give me any greif. I should be able to shop barefoot anywhere without having to choose areas where it's ok!
perhaps using this handy link might help in future http://www.hse.gov.uk/myth/myth-busting/2014/case297-supermarket-barefoot-customer.htm
You may find this hard to believe but my Phil was asked to provide ID when buying a bottle of gin from Tesco.....he's 63!!! Admittedly the checkout girl was new & very young but for pete's sake!!!