We had about eight CLOSED signs; two in front of the register, three on the ice-cream display, three more in front of the espresso machine. People still came and asked us if we were closed.
When I worked at a bar our urinal stopped flushing, so I put the laminated "Out of Order" sign over the bowl. We had a lot of customers walk out of the bathroom with a line of piss on their pants from the splash back from pissing on the sign.
Once you work with the public long enough you're no longer surprised by such things.
The saying "There's substantial overlap between the dumbest tourists and the smartest bears" is very true even though it was never said by someone in the National Parks Service.
I've met plenty of people who I believe would be outsmarted by the average bear let alone the smartest bears.