How? Would that be illegal in itself in China?
> livestreaming their trip back to BBC HQ
Maybe doable if the local phone reception is good enough and not blocked (remember, the great firewall throttles VPNs)
> having an agent buy their tickets/hotels so it looked like a local was going instead of the BBC?
Is this in and of itself legal in China? Or is it one of those places where you have to register your passport number at the hotel?
Part of travelling as a journalist is doing so openly as much as possible - covert journalism runs the risk of being deemed espionage, which can result in a death sentence.
It is not legal, no. Travel on railway and plane and booking hotels all require you to present your ID, as is signing up for a mobile phone.
They interview lots of people with no problems, and they don't know which ones will kick off. They are reporters and their visas are journalist visas. There's no quicker way for them to get kicked out of the country than doing clandestine reporting that embarrasses the government and breaks the law. Lastly, this is the story. In all honesty, people will probably care more about 'BBC journalists attacked' than they would the original 'Chinese citizens human rights abuses'.
Most attackers (low level, local politicians) will be unable to break this most of the time, which would make for a safer situation for all involved. I think that this should be standard procedure in every country, subbing in Signal Private Messenger where it isn't blocked.