A mate of mine and some of his work colleagues
often play pranks on fellow workers by sabotaging their cars in time for the end of work. Perhaps he is just paranoid about something similar?

Even if this is the case, it's not exactly justified as I'm guessing this sort of prankage is not a common occurrence at your place of work.
(ConanTroutman thought we would free the vulture, Thu 15 Dec 2011, 16:42, Reply)