A few years back a guy in my PL had an UD with an AUG. He had the rifle slung across his back while carrying stores to make a strong point.
He had gone thru some bush repeatly, doing a slow jog, as the rifle slapped against his back the safety went to fire, and coming thru the bush again a branch got caught in the large trigger guard of the rifle, discharging a single shot, while slung across his back, and with his hands full.
The member was indeed charged. No injuries.
The safety catch is a poor design and after repeated UDs in theatre (and on Ex etc), DMO came up with a test (and a gauge to measure). The safety catch needed a mininum of 3kg pressure to go to fire. This made about 80-90% of rifles 'NS', and caused a shortage force wide of safety catch srprings which took almost a year to procure. A new spring was designed, and the pressure was dropped from 3kg to 2.2kg, and thats where it stands right now.
The unload drill after the 1993 Somalia death simply means the barrel has to be removed in EVERY unload drill and for 'inspect weapons'. A steel barrel wearing on an alloy housing, and this is not good. The barrels have indeed over a short period damaged the front of the housing, causing unnecessary damage to the rifle. Mainly cosmetic in nature (causing burrs which have been known to cut soldiers), but all the same, the rifle has never been designed to have the barrel removed each time you do an unload. It was ment to be removed for cleaning and changing the barrel length (ie from carbine to rifle, etc).
To combat weapons competancy all soldiers, all trades were required to carry a weapon loaded with blanks during their normal work day (even in the office). NCO's barked out T'sOET daily, and over time even the clerks became much more competent than they were before. Any UDs were met with a charge bearing the same as if it was a live rd.
Another feather in my cap in my dislike for the AUG. Although I have confidence in the weapon, I am prepared to carry one anywhere anytime, I would prefer a M4 any day.