Caveat Emptor

Caveat emptor is basically the principle that the buyer alone is responsible for checking the quality and suitability of goods before a purchase is made. However with pre-packaged goods and gift wrapped goods, a level of trust is required on the part of the buyer. However if the goods are faulty, then the buyer usually has the option of a refund, the best of establishments particularly at Christmas, don't even require a receipt. However there are some who seem to have not taken the old maxim that 'the buyer is always right' to heart...
Mail.

A businessman sold a lump of clay instead of an iPad by Tesco was arrested on suspicion of fraud when he complained to the supermarket giant.
Colin Marsh, 47, paid £470 for the Apple tablet computer in Whitstable, Kent, as a Christmas present last year for his young daughters - but he opened the box to find it contained three lumps of clay.
The father, who runs two bakeries, immediately took it back to the store for a refund - but instead of reimbursing him, Tesco staff became suspicious and reported him to Kent Police.
Two days later Mr Marsh, father to Maddie, 11, and Daisy, eight - got a call asking him to report to his local police station where he was held for three hours, and accused of trying to scam Tesco.
He spent two months on bail before being told he faced no further action. The iPad that should have been in the box was tracked down to Wales, more than 200 miles from where he had bought it.

Now Tesco have of course apologised and the errant iPad has been found some 200 miles away in Wales, though how it somehow managed to have been registered to him, Tesco have yet to explain, nor have they explained just how the supposed tamper proof seals were bypassed. I'm still not entirely sure whay a story of last Christmas has eventually turned up at the Mail some 11 months later.
Still, you do have to wonder at just what the hell the police and Tesco were thinking, tracking an iPad isn't too difficult as they have a unique registration IP for each pad which means one can be located to a server within hours and presumably a call to the address in question would have given them answers including who sold it too them (assumption on my part) or what link they have to Whitstable Tesco's in Kent.
Still I suppose the police can congratulate themselves on another addition to the DNA database...
After all, 'Every little helps' as a certain consumer giant is known to say.