Interesting question, the exact statement is here
https://news.met.police.uk/news/sta...eo-of-fare-evasion-incident-in-croydon-470067 , but the bit about that bit said:
“The woman involved in this incident was asked to provide her ticket as she got off the bus, but did not do so. She was spoken to by a TfL inspector, then by a PCSO and finally by a police officer. She continued to try to walk away and did not provide her ticket for inspection."
The way I understand that, is they can request you to stop, and show your ticket (like the TFL guy did and like the PSCO did, and finally like the cops did), and you're welcome to decline all of those of course. If you decline to show your ticket to TFL, then you have to provide them with your details so they can give you a penalty. You're welcome to decline to do that too, but they have a zero-tolerance policy for fare evasion (which they would be fair in assuming), so will get the cops involved. If you decline the cops or don't respond and they suspect a crime, then they might issue an order or just stop her from walking away.
What is also interesting is that the whole thing was a pre-planned operation, so it seems like they were all there in advance, to some degree. TFL, PSCO and the cops. Bus stops, TFL guy checks all the tickets of all those coming off, then goes on the bus checks all tickets of those on the bus, and then gets off again. Any problems and he calls over the cops. Probably explains why two TFL guys were there, rather than one. Not sure whether the PSCO was with the TFL guy checking tickets, or the cops originally.