You can pay for small items such as a coffee or a paper with a new "contactless" card. Just wave it in front of a card reader and you're done. But, the signal it sends is an invitation to high-tech pickpockets.
For instance, you could be using your new card to buy a newspaper, blissfully unaware that its details are being captured, so you can be ripped off. Even worse, you could simply be in the street or queuing up for a coffee and have the card in your bag or pocket--it can still be read by a crook armed with a card reader.
Source: The Guardian, http://www.guardian.co.uk