It happened to me, but I was the one who recognized her. We had already interacted with one another for a while, so we kind of knew each other a little bit as well as knew we lived in the same general area. One day, I was at a local pub eating dinner at the bar and enjoying a beer while waiting for the band to start playing. This gal comes walking past me, that looks like said model.
Didn't say a word, just thought "Wow she looks just like So-and-So." She walks past a few more times, and I'm fairly certain it's her. But, because she was with other people, I didn't want to stop her to ask and potentially ruin her night.
Next time I see her online, she's talking about that night out with friends. She mentioned a couple of key things that happened, which confirmed it was her. So, I sent her a quick message saying I was there, and saw her but didn't want to bother her for above reasons as well as respecting her privacy.
After a bit of discussion, via PMs to confirm it was me and I was really there, we agreed to meet in a public place. She was with a group of friends, including her boyfriend. She and I sat and chatted for a little bit just to say "Hi" and personal introductions out of the way.
Since then, we've stayed in contact offline and have become good friends, including her boyfriend and I. The three of us will get together on occasion when there's something going on. I still respect her privacy, so don't overextend my stay when we do get together. Nor, do I constantly hit them up with messages all the time. I just treat them as regul
This definitely isn't the norm for most, as most are like you say Elay. Wanting privacy and to be left alone. Which I'm happy to do, as I see most personalities/celebs as being bothered by others, I'd rather just let them be. But, this situation was a little unique. Had she of quickly dismissed it. I would have left it at that and respected her privacy from there. There are a few others who I know are in my general area, or an area I frequently travel to. But, aside from a bit of chat or banter online, it's never gone beyond that.