Cararies are domesticated, and easily caught and extracted from a cage or aviary. Wild birds are a different matter, being much more highly-strung and wriggly. If it was so easy, there would not be an average 2 year training period for ringers.
I can't see any damage at all. But it's spring so feathers are getting quite old anyway. It might have also been kept in captivity for a period (days/weeks) before being released. Birds born in captivity do not have damaged feathers, they are usually pristine as they don't have the wear of wild birds, and a bird hatched in an aviary doesn't feel the need to bash up against the wire like a wild bird would.
It could feasibly be a captive bred bird that was not closed-ringed, and then escaped or was released deliberately, but this is almost inviting prosecution by the RSPCA. They are very active in raiding keepers of British Birds to try and catch illegals, and anything without a closed ring is viewed by the courts as wild-caught. There have been several high-profile cases lately. So virtually everything legal is closed-ringed, and it has to be anyway if they ever want to sell it. You can swap without colour-rings, but nobody in their right mind would take it off you and risk a court appearance and confiscation all of their birds.
So the chances of it being legal in any way are vanishingly small. But we don't know if this happened in the UK or somewhere else (I'm not sure if it's illegal in e.g. Russia)