Yeah for the movie co’s going to ISPs with an IP addy that was suspected of torrenting is one thing, but for BBC to go to every ISP with every IP is basically suspecting every user of iplayer of being a criminal. Not going to happen.
Login account perhaps. Might happen, might not.
Germany did it the easy way. Ditch licence, and effectively make it an extra charge on the council tax, which funds various tv/radio stations both national and regional. If you don’t watch telly, or catchup, (especially if one of those that’s smug about it) then that’s your problem.