So apparently the latest trend out now is to scan people's credit cards with a freely available scanner jerry rigged to a battery, then hook said scanner into your PC and get the info that way. It only works on the wireless cards, ya know the ones with the Paywave symbol. And get this: most people don't even know they had that feature on their cards!!! Not to mention credit/debit card makers want to convert to this in two years...
Yeah, it looks from that video that the reader has to be swiped within inches of the cards, so using it on random people without alerting them seems highly unlikely.
yeah, there are situations where you're really close to people. You could probably walk around a busy area with the thing just on yourself constantly scanning and collecting cards, since you'd likely come within inches of people, or even brush up against them unavoidably.
Maybe these people were born without that part of their brain that lets you try different things to see if they work better. --Retsupurae