I think they've thought of that with an interlck on multiple use
So it is sooo secure you are prevented from making multiple purchases with your own fucking card in case somebody nicks your card...? 
I don't know, they are not gong to give away all their secrets
All I know is
they are saying you are 100% protected against fraudulant use so there must be safeguards. Too quick a repeat use would be a simple one so would insisting CCTV cover where they are used.
But they work well and you don't have that "is someone clocking my PIN" issue so I like them
[/serious mode]
