I am pretty much agreeing with the article as well. I never use soap, I shower, then rinse forever or if I don't shower, I wash the area with water and sometime use Vichy's thermal water. I rarely use the paste now that I use the complete "gum/paste"( I don't know how to call that substance) and without the "paper" adhesive. I generally will use the karaya powder when I have irritation. I was taught to powder, spray, powder, spray the area and that as always worked when needed. I use to skin prep the whole area but it never did much good to me and I ended up seeing it as an unnecessary expense as far as I was concerned. So yep, forgetting the skin-prep should not be too much of a deal unless it helps your skin from a reaction to the appliance itself as 2thFairy said.
A big no no is soap like dove soap... that, on the other hand, really can prevent the appliance to stay on. Too much hydration coming from the lotion in the soap. :S