I've heard about RFID-shielding wallets and even individual card sleeves, but my wallet has multiple RFID cards in it (credit card, bus card, building entry card), and if I tap my whole wallet on a POS reader to try to pay for a transaction, it fails.
Why does it fail? Is the reader only reading 1 card with the strongest signal, but it's the wrong one (for example the bus card)? Or is it reading a mixed signal which it can't interpret?
Does having 2 RFID cards in a wallet cause them to shield each other from any possible attack? (even though I understand there aren't many attacks to be concerned about at the moment)