I did some research on this and heard that it worked pretty well... BUT there are some disadvantages. If you accidentally pull on that line (which unhooked for example) the kite could invert. Also, the waroo is not designed to be loaded at that spot... and the additional drag in heavy winds may also lead to inversion.

Also, unless you have a stopper set on the 5th line, the kite will fly upside down (probably able to pull you but not with any real power).

Now for facts based on experience? I have none... I haven't tried it yet. I have been thinking about it though.