This is not something I believe that can be remedied by merely sending a pm or banning the provider from cerb or whatever. Anyone that does not understand how wrong this is to begin with has deeper problems.
I hope she sees this and realizes the error of her ways, because the next step here will ultimately lead to losing her child. And what can we do? Nothing. If she doesn't get the shit scared out of her from that possibility, she can be tossed from cerb and will go back to getting more dates on CL. One day, all this info will come out and she will have her child(ren) taken away.
And for all intents and purposes, this should stay as a warning here because I wouldn't want to be in that apartment with my pants down when the police and/or children's aid comes knocking.
Most accounts of this sp have generally said that she is shy and pleasant, and chances are she is a decent person trapped in some way into what she's doing where the consequences are not prominent to her. Who knows what that trap is - financial, psychological, coercion, etc. But my opinion is that we can do nothing. No one really knows enough to take it upon themselves to contact the authorities...that could effect a few lives in a very serious way.
And if the sp in question reads this, please seek help for your situation. You may even find some people here that can assist you.