I've finally figured it out! I always thought it was funny that they back up when they do their "thing". Friends always comment about it and I say "that's just the way they do it". But there really is a reason. Very smart when you think about it. We've all heard the saying "keep your back to the wall", well that's what they do to protect against an ambush when in a vulnerable position. The beep, beep is the signal we use as a warning of a potential "illegal dumping". :-) SP [Posted in FML issue 2188]