People are too uptight about smoking weed.
It's like buying a hooker. You're not gonna forget her in plain sight where anyone can see you. That's just loving stupid.
If you do smoke, I doubt you'll be caught.
If she gets high and wants to forget, she wants to get high and forget. Smoking weed won't cause you to black out and forget everything. It just makes you giggle and relax, really.
You're not going to rape a girl who says yes.
Just smoke it with her, and see where it goes.