Nomad

There is actually a term in the retail industry for this and its called "grazing". I had an interesting chat with the manager of Tescos in New Malden, an American originally and he explained that up to £10,000 of stock was consumed a month at that store alone and not particular to the UK but a world wide phenomenon. Not just the odd gr a p e but some helping themselves to pies and a drink or maybe the odd sandwich while they shop. Some know its sealing but some actually don't realise it is wrong and some intend to pay for the consumed goods at checkout but forget. One reason why the pick and mix section was removed because of more stock being grazed than bought at one point. Unsupervised children can often be responsible for such losses as they are not always aware that their actions are wrong and that is up to the parents to teach them.

The bottom line is grazing is factored into the cost of your goods at your supermarket. As you said people think its just one gr a p e but when 20,000 people have the same thought thats an awful lot of gr a p es!