This is supposedly a true story from a recent Defence Science Lectures
Series, as related by the head of the Australian DSTO's Land Operations / 
Simulation division.  They've been working on some really nifty
virtual reality simulators, the case in point being to incorporate Armed
Reconnaissance Helicopters into exercises (from the data fusion point of
view).
Most of the people they employ on this sort of thing are ex- (or future)
computer game programmers.  Anyway, as part of the reality parameters, 
they include things like trees and animals.
For the Australian simulation they included kangaroos.  In particular, 
they had to model kangaroo movements and reactions to helicopters (since 
hordes of disturbed kangaroos might well give away a helicopter's 
position).
Being good programmers, they just stole some code (which was originally 
used to model infantry detachments reactions under the same stimuli), and 
changed the mapped icon, the speed parameters, etc.
The first time they went to demonstrate this to some visiting Americans, 
the hotshot pilots have decided to get "down and dirty" with the virtual
kangaroos.  So, they buzz them, and watch them scatter. The visiting 
Americans nod appreciatively...then gape as the kangaroos duck around a 
hill, and launch about two dozen Stinger missiles at the hapless
helicopter.
Programmers look rather embarrassed at forgetting to remove that part of 
the infantry coding...and Americans leave muttering comments about not 
wanting to mess with the Aussie wildlife!  As an addendum, simulator 
pilots from that point onwards avoided kangaroos like the plague, just 
like they were meant to do in the first place.