Tossing water at electric fire
Some years ago, our campus changed the outsourced company in charge of the logistics (gardening, security, maintenance, etc.)
The new company deemed necessary to replace all the existing fire extinguishers (don't ask me why, the existing ones where still good, of the sealed type, so no leak).
Anyway, we got nice and shinny new fire extinguisher, bright red and full of compressed water. I had quite a fight to get them replaced with ones that were computer compatible.