Well, hardcore porn used to be illegal.
In the US, amongst other things, it would be prosecuted under the anti-prostitution laws.
Eventually the courts ruled that hard core porn movies were not the same as prostitution because the people having sex were actors acting, and it was then allowed.
I'll bet that you could legally have sex with SP's, including openly advertising for it in ways which aren't currently legal in canada, as long as you filmed it. You would, however, have to go through all the motions of making it look like you were doing a real film.
I don't know if you would have to attempt to sell the finished film or not. You could always claim it was an art project. Artists do not have to sell their work if they don't want to.
However, this won't do anyone much good, as your average SP is certainly not going to allow you to film her.