They've been identified and the entire group seemed to be settled in the UK and possibly even UK nationals through naturalization. I might have been ahead of myself thinking they were foreign visitors.
It was really weird because there were so many moving parts and they brought up image rights as well as some nondisclosure agreement they signed about the activities they were doing at the station/mall. And the gist is that they had an agreement that their activities had to be super secret until their video was broadcast, but required that they record everything in a train station/mall.
Frankly, nothing that's been revealed since helps their case.
They were still in a public place, and while they may have been bound by NDAs, others are not, nor are they responsible for keeping your secret. If the piano guy was intentionally taking footage of them, and others, he'd have to get releases, but he wasn't going around shooting other people, was he?
A professional crew would know that when shooting in public, the onus, so to speak, is always on
them to conduct themselves without being disruptive, or breaking any laws. Not the other way around. The tail does not wag the dog.
Finally, common sense would tell most people that if you don't want to be captured, get out of the shot. Even the most basic tourist knows to scurry out of the way when someone else is taking a picture, and they don't want to be in it. Common courtesy.
It would be a shame if this lead to some sort of permanent removal of the pianos, or something of that nature, perverting the reason why they were put there to begin with.