Re: What could possibly...?
@Lee D, "Keep your debit card in an RFID blocking wallet or sleeve."
Or just ask your card issuer for a non-contactless card. I'm not a tin foil hat type, but I wanted non-contactless versions of my credit and debit cards. I asked my card issuers and they happily sent out non-contactless replacements for the pay by bonk cards they normally send.