Originally Posted by dscheidt

WD-40 isn't magic. It's light oil in deodorized mineral spirits (kerosene, essentially). The film that's left is oil. it's not the right thing for any job, but it's hardly awful. It doesn't make a good lubricant because the ratio of oil to solvent is too low, but it's unlikely your coworker got enough into the parts of the chain that need lubrication to matter.