Don't think I've encountered any Thai that won't accept qr payment, all the market stalls, roadside stalls and shop have their qr code prominently displayed.
And if they didn't I'd ask "sakan Mai".
You scan the QR code, show the shop-keeper the name on the screen (check or enter the amount) and ask 'is this you?'
Now explain to me how there can be fraud or theft?
I would define scam as paying a 400bht bill with a 1000bht note, and being given 100bht change ............... "no, you gave me a 500bht note". Probably the most common taxi/bar scam in Thailand.
How many times a day can you afford to lose a tenner?
I would, used to carry an angle grinder in the boot of my car back in the UK.
Sometimes I randomly removed 'boots' from other cars.
Best not to let anyone video you doing it though, pull your hoodie well up!