Richard, yes many people fertilize their orchids by spraying the diluted fert onto the leaves, stems and the roots. Orchids do absorb most of their water and nutrients through their leaves. The function of the roots is mainly to anchor the plant.
I've been using alfalfa pellets widely as a soil amendment in my garden for a couple of years, and I think lots of plants love it. Yes, last year I did spray my orchids with alfalfa tea a couple of times - had to filter it through a paper towel into the sprayer so it wouldn't clog things up. Hard to say whether it had any effect as I'm also using a couple of other soluble fertilizers, but I'm sure it didn't hurt. I'm going to do it again this week.
