To be honest, I never do in any case - except my wife. I find that's a fairly safe rule of thumb. But I do think everybody objectifies - men and women - whether they admit it and discuss it outwardly or not. And as you point out, if they are looking at a stranger, that's all they have to go on at that point in any case.

I'll be honest: Prior to meeting my wife, I would sometimes see a beautiful woman and be attracted to her. But if she couldn't engage me intellectually, that attraction withered at once. For example, as someone who eats, sleeps, and breathes cinema, I simply couldn't bring myself to become romantically involved with someone who couldn't appreciate good films. I didn't necessarily need her to be a lunatic film encyclopaedia like me, but... Well, you get the idea. :)