On one contract about a decade ago, the manager used to proactively screw around with server hardware (eg pull a hdd out of a raid set) when bored, to ensure our recovery processes were always battle tested.

Didn't generally cause too many issues... until the one time he pulled a working hdd out of a raid5 set that already had a (real) failed drive, which we were already attempting to recover. It was a production database, but thankfully not a mission critical one :>.

From memory, he stopped testing things like that for a while afterwards. ;)