A user Ne6c warned users to be aware of card skimming scammers on the tube.
"Just witnessed some youngish looking duo walking up and down the tube(District Line), posing as "security" wearing all black uniforms and no TfL branding instructing people to pull out their tickets for inspection. Both guys then used iPhones (the part where I really became suspicious) to tap (and I assume scan and skim contactless cards) on Oyster and Contactless cards really quickly. We just arrived at Whitechapel and I was on my way out the door already when one of the guys asked me for my ticket and I asked him for his identification and he immediately skipped me and moved on to next person and I was out of the door.
Now I suspect they were only after skimming contactless cards, so probably no damage has been done to the owners of scanned Oyster cards, but please be aware of these scamming pillocks and always asked the inspector for ID, as I believe that every staff member in the TfL network has to have TfL issued IDs on them while they are working.
Hopefully, I imagined everything and it was just a hoax and people's money won't be stolen.
EDIT: Talked with the BTP on the phone this morning to report it and they're aware of the situation, apparently it has happened before though"
Besides, many people in comments approved that fact and informed about simmilar cases in different countries:
" Most IDs have a number on that you can call and verify. Not helpful on the tube but you can always photo it to verify later - if you have been scammed this would be useful evidence to get your money back (if possible).
No one who is legit would hesitate to show their ID and they'll be hard plastic, credit card style ones. A laminated card is an obvious fake, as is grainy typeface/logos, etc.
Similarly, anyone who is legit will happily discuss further with you/move on if you don't believe their ID is genuine. Only a scammer will try to force the issue." - commented MartynTyrant.
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