Good article, lots and lots of great information there.
Being afraid of large beaks and having a macaw that was kind of afraid of people, I did a no-no in the beginning and let her come out of her cage by herself. I had made a swing for her that I had moved her cage close enough to for her to climb on by herself. Once we got past the "I won't hurt you, you won't hurt me" stage, I started moving the swing farther away so she had to step onto my hand to reach it. I would ask "do you want to go on your swing?" and point to it, and she would step up for me...and there we'd go. Of course, the "up" and "down" command needed to be reinforced, I would say "up" when she got on my hand, and "down" when she got on the swing (even though she would go by herself). I only had problems with her when she turned three and suffered from selective hearing loss--couldn't hear the "up" command and thought I said "pinch me". We cured that with trips to a strange room to work on commands and a lot of pine nuts.
I have always asked mine if they've wanted to come out before I open their cage door, and because they're all vying for my attention I usually have no reluctance on their parts. Each bird has a certain perch or spot that is their "step up" place, and if they don't want to come out when I ask, then they won't go there. Simple, and has kept me from spending a small fortune on band-aids. They come out when they're ready. I can always find a magazine to read to them until they are.