The Paralympic Games is probably the only place in the world where you can be discriminated against for being able-bodied.
As soon as the Games began, we had the first example of this.
Australia's Jess Gallagher planned to take part in a number of events, including the sprints and long jump, and had hopes of gold, but they were dashed when she was told she could see too much.
This really is the one place where you could be devastated by being told that your sight was better than you thought it was.
There is no suggestion Jess was cheating; the margin of error is tiny and it only applied to one eye.
But it is enough to get an athlete removed from the village. If you don't qualify as a Paralympic athlete, you can't stay.
Irish soccer player Derek Malone is in a similar position but in his case, the improvement which the testers say has occurred in his cerebral palsy, is, irony of ironies, the result of playing football.
He is convinced that his range of movement has been improved by his sports training. But that's dangerous!
After a good game while the testers were watching, it was deemed that Derek's disability now didn't have a "substantial impact" on his football.
It has led to a standing joke in the team. As soon as someone starts to play well they get a warning from the rest of the team in case the classification police are watching. There is no way round it.
Everyone, the athletes in particular, accept that if they want the Paralympics taken seriously, classification must be adhered to rigidly.
But where else would people like Jess be writing home saying: "Dear Mum. I don't know quite how to tell you this. They say I can see better than I thought I could".