"But an Iranian journalist based in London who initially posted the footage has insisted that his source is safe, and that the Iranian authorities have arrested the wrong person."
or the actual source is the one being arrested and the journalist is trying to trick the government to release the person.
I thought about that too but media have a lot to lose in terms of credibility if it gets exposed. I'd bet you there was a NYT lawyer in touch with that journalist ASAP when they published that tweet if the journalist hadn't been in touch with legal beforehand.
Unless your point is to send a message. But yes, still even worse.