Initially the airport succumbed to the pressure from prude passengers, as they covered up the risqué reproduction. However, eventually they decided that people should be able to handle something like this, and they decided to let the advertisement and art do its thing.
We agree with the airport’s decision to just leave the thing up. If anything, this has probably brought some attention to the exhibit and the museum, so hopefully they'll get their wish to sell even more tickets.
If you’re interested in attending, the Picasso and Modern British Art exhibition runs through November 4 and tickets will set you back £10.