In one of my more funny experiences, I was rehearsing some upper management speakers at Upjohn headquarters in Kalamazoo, when I saw what I thought was a runaway office-cart. I ran down the hallway and grabbed it, tried to stop it. A half-dozen secretaries came out and started hitting me with file folders, ledger books, etc. Turns out it was a roboticized cart following an invisible sprayed-on trail along the carpeted hallways. It would follow the path to a 'cross', stop and beep until someone checked it for physical mail or deliveries, wait for a button press, and then continue.
I was more angry than embarrassed. "What the hell. They're too cheap to HIRE SOMEBODY?"
Yeah, well. '89.