IBM asked me for a password
In about 1987 we borrowed a 6150 from IBM for use at a trade show. The 6150 was IBM's first AIX (their Unix) machine. It did not have a lot of disk so I removed about 1/2 the operating system so that we could make a decent demo of our application.
After the event we returned the machine.
A fortnight later I had a call from someone in Warwick. They wanted to know what I had changed the root password to. I told them, but was astounded that IBM were not going to just completely wipe/re-install the whole operating system - I would not trust a machine that had been loaned out to someone like me!
Also: did they not know how to break into their own machine at the hardware level ?