I unclip right.

Someone actually asked me the other day whether I was left handed (I'm not). They said that most everyone that's right handed unclips left.

I don't know that the horse analogy holds, either, because on a motorcycle, you always put your left foot down first (because your right foot controls the rear brake). If foot-down habits translated from other sports, you'd think that motorcycle habits would translate to bicycles a lot more strongly than horse habits.

For me, I think it's the curb thing. I had years of urban commuting before the ADA. Nowadays, that doesn't hold, especially where I live now. The other riders in my club are mostly (though not all) younger than I am, and most of them grew up in the community we now ride out from... small to begin with, and blessed with miles of bike trails we can use to get out of town and onto the "real" roads. So on the rare occasions when we're even around curbs, there are wheelchair cuts which have probably been there as long as most younger riders can remember.

Interesting....