Hey Ron, have to say that many folks have worried about decockers causing an AD, but I have not ever heard of one happening on Walthers or Sig's. Actually the only weapons I have personally known (through officers I know personally or having been present) that have had an AD while fingers were completely off triggers, are 1911s and one Glock. The 1911s went active (full auto) due to worn parts, when the slide was released into full battery. The Glock fired when the slide was released from slide lock and to this day, noone knows why. I personally witnessed the officer and know his finger was off the trigger and even Glock cant explain it. The only saving grace for the officer was it was caught on the dept's internal camera system that proved his finger was off the trigger.
Wouldnt worry about it, but as ALWAYS, keep the barrel pointed in a direction that provide you with the best back stop incase of an AD (something I do each and every time I do a press check before leaving for work).
One thing I did was take an old vest of mine (you can buy an old used one for this purpose) and put it behind my gun box in my closet simply to work as a back stop when loading and unloading weapons.
Hope that helps a little.