If the stolen cards are used by underage drinkers they could buy as much alcohol as they want.
The self -service check-out could cost a _lot_ more than the money than Tesco are attempting to save
I Tesco are wanting to provide a better service on the check-out they need to adopt the policy of Lidl or Aldi where the customer throughput per staff member must be around 10 times greater. Doing away with vouchers for schools and the 'cash-back vouchers' would save them millions of GBP in time saved at the check-out.