Sometimes, when you think you've invented something that nobody else has ever come up with, you need to step back and realize that maybe the reason you were the first to think of it is because it's a horribly stupid idea.
If you really have to go, and there are no bathrooms around, you aren't going to take the time to put on some weird-*** piss raincoat; you're going to go behind a tree. No trees? Then you're in a city, stupid; go find a bathroom.
What if it leaks? What if you forget to drain it or replace the bag or whatever? Who would walk around all day carrying a raincoat full of their own urine?
I wish I could slap this guy for being a tard, but the knowledge that he wasted his time and money on such an idiotic scheme will have to do.