When a model is in a private show, not all viewers will be able to see or interact with them.

You'll see which models are in a private show, firstly on the front page, by checking the picture of them, which would show a mask in the top left corner, as seen here:

If you click on the model's image, you'll get this page showing the model is in a private show:

You'll also see ways in which you can spy on the show, with prices and the free time given.