it's actually so you don't spend longer than necessary in the cubicle, if you can be seen, the idea is to do your business quickly and vacate for another.
Well if someone can see you, you probably wouldn't be doing your business very quickly. ( at least I wouldn't. Don't know how guys can use a urinal with someone by them )
And imagine it. Someone's looking through the crack while you're in there " come on dude, hurry up. I gotta go. Are you done yet ? "
One time I was in a public restroom putting in a tampon and I looked up and a little kid was pressed up against the door watching me. The worst part was I was at a swim meet and I had already swam an event and I got my period so I went to the bathroom and because I was in a one piece I had to take off my swim suit so I was also completely naked with this little girl staring at me.
And imagine it. Someone's looking through the crack while you're in there " come on dude, hurry up. I gotta go. Are you done yet ? "
*makes eye contact through gap*
*starts sweating*
*gavin screaming*
*helicopter whirling*