Being in the mechanical trades for most of my career, this doesn't really surprise me anymore. It scares hell out of me, but doesn't surprise me. I have seen some things that will curl your hair.
Coincidentally, just last week one of the maintenance guys here at the institution, and knows some of my background brought a picture to show me that he took in one of our very own buildings. It showed a look up through the ceiling (tiles were removed) where someone in the distant past had very carefully wrapped duct tape over a very small leak/drip at a joint on the 'fire suppression' water system in the overhead. I thought now just how the hell any pipe fitter, or even a general maintenance man could have thought that duct tape would ever hold a water leak under pressure???
Turns out he was a little smarter than I gave him credit for I guess .... after a little closer examination of the tape repair, it became obvious he had left just one little portion of the tape loose to form a trough of sorts that directed the leaking water to a drip pan he had placed in the overhead. Understand now, there was no drain from the drip pan, it just caught the little drip from the taped joint.
Apparently at the time, the drip was slight enough that the water caught from the drip would evaporate before over filling the drip pan. Well, that was some number of years ago so we figured either the leak got a little worse over time and caused the drip pan to overfill and leak on down onto the ceiling tiles, or the sides of the drip pan rotted down to a shorter side and allowed the water to overflow onto the ceiling tiles before evaporating.
This will be a funny story to most folks with a mechanical background, maybe not so much to the rest. If not, my apologies.