There are several blind or visually-impaired people living in the Davis Square area, who use guide dogs. I occasionally see them going about their business when I'm going about mine. Once or twice I've even ridden the bus with them and their dogs.
A few days ago the kids and I were in Davis, and it was one of the first really beautiful weather days we'd had so far this spring, so there were LOTS of people out and about (including
lbmango, into whom we bumped that day). Of course, in addition to people, there were also lots of dogs out and about, so Ruthie was in toddler heaven because she's in a major dog-loving phase. So she was basically dashing from dog to dog in a high state of excitement (and btw I have been working hard on her to say "Is it okay if I pet your dog?" before petting, which she is doing pretty well with, but that's a whole other post).
I noticed two blind people standing in the square chatting, with their seeing-eye dogs sitting next to them. So I just told Ruthie, "no, we can't pet those dogs, they're working," and she gaily skipped on to the next dog, and I thought no more of it at the time.
But later it got me to thinking. If two blind people pass each other on the street, how do they know? I mean, if a blind person and a sighted person who are friends/acquaintances pass on the street, the sighted person might say "Hey Bob, how's it going?" by way of calling the blind person's attention to his/her presence and initiating conversation. But if they're both blind, they would never know that they just walked right past a friend. Unless maybe the dogs recognize each other and bring them together somehow?
I dunno. These are just the weird things that I think about when left to my own devices. ;)