The lubes may have improved over the years, but I have seen a "flash over" situation with lube dripping from an overhead pull onto buss terminals.Some types of lube are conductive and you should not energize the circuits until the lube has dried for that reason. It is not simply a CYA. I do not know how long it takes to dry.
It may have been the lube or contaminants it pickup up, but it showed itself to be conductive.