Creating a 'cloned' physical second card with contactless capability is technically very difficult and quite rare due to having to replicate the encryption technology contained in the chip. Cards with magstripes containing unencrypted data are much more easily cloned but you need to put the card in to a skimming machine - this is why this happens a lot at cash machines, petrol stations, bars etc where you hand over your card to an unscrupulous actor.. What can happen today is that your contactless signal can be relayed via a transmitter to a payment terminal which is fooled in to thinking your card is present and a purchase that is already in progress is authorised. Same principle for stealing cars where the keyless signal is amplified from where the key is to where it needs to be to open the car.
It should yes, as it will refuse to provide the positive confirmation that the terminal is asking for. Card data can be harvested in many other ways though - stealing of data when making online purchases or hacking card data held unsecurely by organisations is a greater risk.
How about having a pre paid Mastercard https://www.mastercard.com/gb/en/personal/find-a-card/prepaid-card.html
Interesting conversation, the last time I used bank cards was when in the US, since I moved to the NL, I've been using a digital only bank for all of my transactions and leaving my main accounts entirely remote. When travelling, anywhere, I take a backup card but I can't remember the last time in the past 5 years that I've used it instead of my phone. As a result, I feel very secure when it comes to things such as cloning.
I've got a little shield wallet, just bigger than the card, stops the card being read apparently, fits in your front pocket which is the real advantage. Had a strange one with a Barclays debit card, new card, new code, didn't work, they thought it was a faulty chip in the card, no idea, new one on order.
