Tarzanman, and everyone else, the area I was learning on was packed, blown on man-made snow, pretty close to ice, and I did fall with the full weight of my mid-section onto my buttox. I think I even fell a little to the right, which probably aggravated things since the impact was not directly on the tailbone foam and plastic shield protector.
I think it has long been agreed upon that the best tailbone/butt protection available is either the azzpadz or skeletools, since both, as stated above, offer more surface area and thicker padding to disperse the blow. But this is also their downfall, as they are a little more bulky than the rest. But the nice thing about skeletools is that you can remove layers of padding or remove it entirely from certain sections to suit your needs.
I like how low profile, comparatively, my Demon DS-1450 low hard tail shorts are, which is why I am going to keep wearing them and see if it happens again. I know of several people on this forum who use them without issue, and possibly mine was just the way I fell. I would not dissuade anyone from buying them. I have researched impact shorts heavily as I prepared for my first day of snowboarding, and I can honestly say I think the tailbone protection/impact shorts I have mentioned above are the top 3, at least in my mind, to choose from.
And please know, I'm not trying to argue with anyone here. This is just my humble opinion!
gregc4, I highly recommend you get some impact shorts of some kind. These things saved my butt... and it would have been alot worse without them!