There are 2, I can confirm that as a fact. Or, were 2, the second appeared around the 20th. I don't know how it was confirmed as an escape, but the one before that was verified as of unknown origin for a very long time.
Yes, I agree that the 'owner' of the bird is not the owner, because she has made outrageous mistakes about the bird's gender which in my eyes immediately and unquestionably rules out ownership.
When the bird first appeared, no-one reported any escapes (unlike with the second...), and when I saw it, I was observing a wild bird which was showing distinctive signs of being wild, completely unlike what I would expect a captive bird to behave like.
I do not know anything about the Facebook threads, except that it all sounds like extreme trolling. As does Twitter, where people have been making fun of people's year lists which included the bird (mine does as well). I do, however, know as a fact that it was seen on the 28th Jan, and afterwards.
Bottom line is, if you want to see it, do go and see it, and decide for yourself what you think it is.
Ultimately, lack of 'observations' could be down to a lot of reasons. Claims abound like wildfire, and nobody will chase after it if Birdguides and RBA stop reporting it, which lost interest the moment the captive individual appeared.
Time to stop entertaining this and go see Slimbridge's wild cranes (which are never reported on Birdguides/RBA, note that)