It reminds me of the whole “if you see someone shoplifting, no you didn’t” thing. I have also skipped out on a lot of Metro fares in my time, because I had zero income and needed to get around to interviews or, god forbid, actually visit a friend once in a while. Got caught once, but since I did this regularly for most of a year the fine was well worth it.

Nowadays I’m much better off (can even afford food! gosh!) so I’ll happily pay for such an important service.

All that said, it’s possible the people you saw just don’t know they’re supposed to tap out as well as in. Some of the buses near us have started doing the tap in and out thing instead of interacting with the driver, and I swear I’m the only person I’ve ever seen actually tap out as instructed. Whether the people who don’t tap out get charged more, or whether I’m doing it unnecessarily, is unclear. Maybe it’s something to do with the current £2 fare cap. No idea. But those were the instructions so I’ll keep doing it!