dangerous perhaps but did you never try to piss out the side door?
Because of either
A. The wind would have blown it back into the cabin at all the passengers because we flew doors open most of the time because of the heat.
B. If above said doors were closed the wind would spray and blow it all over the windows of those doors and I would have to clean it up when we landed, thats also if the wind did not blow it all back over me.