ORIGINAL: The Raven
I have a trainer with close to 150hours or genuine air time on it.
The connectors have gone green but I've never suffered any problems. Some may call that luck but as long as you wipe them clean and the gunk isn't inside the connector it's not worth worrying about.
That one is a potential problem.
I splashed a Seamaster last summer from exactly that -- corrosion on the battery-switch connector.