Ive done it before by myself and as well when me and my mate taagged up a chick and the girls seen the camera and they were keen, if they are keen to come back to the pad to fuck after hours of meeting you generally there dowm for anything! But not all girls are obviously, and who cares if you show all your buddies if a girl gives it up the first night shes not girlfriend material so have fun with it! You will know the ones where you can get away with it and the ones you wouldnt even dream of doing it!
On a side note its fuckin creepy filming a girl without her knowing! I would feel like a scumbag and im pretty sure thats illegal