Bizarre. I unclip with either, depending on the situation.

If I pull up next to a curb, the right one often comes out giving me the option of remaining in the saddle.

If the road is sloped/crowned I'll often unclip and lean towards the slope. At an intersection if I have to dive/drop the bike, leaning up hill gives less distance to fall.

I couldn't tell you which foot is dominant...

Derek Zoolander: I'm not an ambi-turner.