This is a terrible idea, because it kills contactless payments for a large part of society. My mother lost her wallet once and it didn't take long until someone started buying hundreds of dollars worth of cigarettes with her card. As a consequence she decided to disable the contactless payment feature and now has to stick the card into the card reader the old uncool way, when all she wanted was having the pin be mandatory on every purchase.

Finally. UK is so far behind on payment technology, again. It took years for contactless to even appear in the UK at all while rest of Europe already had it. It's the same now - while in Europe I can pay a transaction for any amount using contactless, it just needs a pin - I literally just paid a €2000 hotel bill with my British credit card by just tapping it on the terminal, I just had to type in the pin, simple as that. But in the UK? Anything over £100 you have to put the card in. It's stupid.

So unlimited unauthorized transactions? This is why I disabled the feature the first time I got a wireless card from my bank.