shrug - meet beforehand and give her cash? I did that one. She made me buy her lunch too!
There's no good way in Canada without potentially exposing yourself or her. You could give her the details of an online gift card but then if she doesn't offload it in time, some guys can delete that.
I'm noodling with the idea of her having some sort of rechargeable VISA card that you can send money from your VISA gift card. I'm too lazy to figure out the details right now as I don't really need to.