Are we right not to trust supermarkets?

PA

Any trust we had in supermarkets and their deals is now officially gone. There was a time when shoppers wandered around the shelves wide-eyed, impressed that they could get so much of their shopping for free, and feeling great about the money they were saving.

Now they venture around warily, looking closely at the prices on these so-called offers, and cynically wondering how many of them actually constitute a saving at all. But are we right to be so mistrusting?