I hurry by public bathrooms when I hear the toilet flushing. I don't want anyone stepping out and it looks like I'm standing outside listening for whatever. I'm definitely not. I don't want to hear it, see it, smell it, anything.
I'm funny that way. Plus, I'd prefer not even to be in a bathroom out in public. It's a terrible feeling to have to walk in one. It's like admitting you have body parts and it just feeds people's imagination.