On: TfL's simple pop-up message led to a significant d...

[lpribis]

You can get contactless PAYG prices without any identification in London by using an Oyster card. You can buy them from corner shops without ID, and top them up at the same places with cash.

I doubt this really affords you any extra anonymity though. Tube and rail stations are so heavily covered by CCTV, and the police have many times tracked peoples entire commutes and movement through CCTV only.

[eesmith → lpribis]

To hinder traffic analysis across multiple trips, you should also have meeting where you swap Oystercards with others, similar to how people would (and still do?) swap grocery purchase tracker cards with each other, to get the discount with less surveillance.

[fullspectrumdev → eesmith]

I used to do this with a few people.

The system breaks down when one guy stops topping up their card knowing they can be a prick about it :)

[cwillu → lpribis]

Although somebody used to have to actually sit down and comb through the footage to do that. Although not so much these days, so that point is moot.