You know, I have an idea whereby one might be able to further such contacts despite principles or just plain diffidence (and Palomine, while your principles are laudable, you do admit to kicking yourself for missing such an opportunity). This would be especially useful to those living in L.A. where such sightings appear to be be fairly commonplace.
Obviously, most girls would hesitate when a stranger offers her a ride, or even a conversation: there always a risk of dealing with a crazy (you aren't, of course, Palomine, but how could she know?)
Here's the idea: carry with you business cards with an email address. If your real profession is something conceivably beauty-connected, like photographer, publisher, graphics designer, all the better. If not, you could put something like "BEA Moderator" (true for Palomine) or "BEA Talent Scout" (anyone with the guts to carry this out qualifies as that).
When you sight someone like this, especially if she doesn't appear hostile, smile, hand her a card, and say "Please email me". Then just walk away (unless...unless...she calls you back...but then, you're in, at least for a conversation).
In this way you are offering her an opening without risk to her, and who knows, she might just take you up on it.
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