I own an impedance meter and actually carry it in the van. I probably have not had to use it for 3 or 4 years, but as has been discussed, it's usually a logical solution to dividing the grid and finding the problem. Now, back in the 25 volt K-Mart days, the amps weren't very forgiving to a rouge 8 ohm speaker. You could tell because the amp was hot enough to fry and egg on it :-)
My favorite is the short one side to the ceiling grid. Thankfully, most new construction leans toward open ceilings and not tiles, bridges, and hats.
As far as the pallet on a forklift. Well, I used to stand on the rails of a scissors lift. All of those practices would get an OSHA violation and worker's comp denials. It's strange to be in a harness on a boom lift, but it feels so much safer.
Carl
