The thing is, this really is a freak occurance. So many flights, every single day, over every single city. People need to piss and shit, its simple biology. Every time someone goes for a piss break, someone else needs to be called in? That is just silly and insulting to the people involved.
In the grand scheme of things to worry about, this isn't really one of them. Its ridiculous to feel we need new regulations every time something happens...the next tragedy will always happen. It is inevitable.