I am pretty sure places like Bonga and Stripchat (not sure of others, and I may be wrong for SC?) have an option somewhere/somehow the model can just "tick/enable" so it sets them in "private show". I know MFC has similar but it's "away" mode, so if a model goes on a pvt show on CB for example, they will set themselves to "away" on MFC, or "in pvt" on Bonga/SC, and others.
I think also some models are good at timing it so they can get the member to actually take her pvt on multiple sites at the same time - different people, I mean. So then it is legitimate 1x Private on CB and 1x Private on Bonga, for example.
On Chaturbate they must set a bot/app that allows hidden cam shows or "XX per min" to unhide the screen, whilst they are in a pvt on other places.
Personally, I hate split camming pvt shows, but this type is fine. I don't mind if guys - even on other sites -have to pay a "spy per minute rate" (not a flat-out small XX tokens to see the whole show), as it's no different than 100 guys being on CB and clicking that Spy on Show option.