Every few years, the building maintenance people have to perform tests on the elevators to ensure they meet safety regulations. And the real estate department sends out the usual notice informing the building occupants that the elevators in the building will be taken out of service at various times during the day. They were kind enough to include the following advice:

If an elevator is non-responsive and/or has out of order signage posted, please use another available elevator.

One of my colleagues sarcastically remarked, "Wow, thank goodness they sent that email. I'd have no idea what to do had I seen a non-responsive elevator with an 'out of order' sign posted on it."