Ain't no flies on you!
I used to work in information security. If I had been asked to do a general review of the security of a location, a ploy was to arrive at reception, and then ask - with some urgency - to go to the toilet. If they were inside the building from reception, this often got you admitted into the building without signing in, without a visitor's badge, and without an escort. FAIL!!!
Also highly revealing about a workplace is the signage displayed in office restrooms.
On a more sombre note, I will always remember, after a company merger, visiting the premises of the company we had merged with, shutting the toilet cubicle door, and discovering, on the back of it, a sign with information about the company's employee counselling services. I know it's quite common now, but this was the first time I had come across anything like that, and it did make me wonder what sort of company we had merged with.
The icon chose itself.