11:29 AM
I've heard it's because public toilets lack toilet paper. I don't know if that's an urban legend though.
Not happened to me thankfully.
In Australia, the term "poo ticket" is a slang term for toilet paper. But I have a theory that it's based on a corruption of "pakapoo ticket". Which is a term meaning something that's untidy, based on a gambling game that Chinese people played during the goldrush era that involved hanzi.
I think it's a mondegreen, though I'm not an expert.