Tourists with QR codes maybe not but When I see a Frang at Topps market I steer clear.
Them what pay with their dirty bills.
It is faster to line up behind a Thai woman who appears to be shopping for her family, always with a card. Faster.
Not because it is necessarily, but they know what they are doing.
The farnag often comes back (bellowing, claiming to be overcharged) These are the Chiang Beer vest drunk at 11 AM types, easily avoided.