If Only Everyone were this Open

Well, it was voting time last week. So like a good citizen, I got me down to my precinct polling place and cast a vote. Since hubby was working late (as usual), I was on my own with the two boys. I carried Gareth in his carrier and Theron tagged along behind us. One of the gentlemen helping out new-comers to the area (me) register, told me that I could leave Gareth with him when I went to vote rather than have to hall him over to the booths. Since it was within sight distance, I decided it was a good idea and happily left him there. While I was choosing my candidates, I could hear Gareth giggling and squealing and I was glad that he was having a good time. When I finished, I went back to where Gareth and the man were sitting, thanked him for his kindness and got ready to leave (Theron, meanwhile, had been roaming the area and had finally come back to where we were).
The man said, "It was no problem. I like kids . . . but can I ask you a question?"
"Sure," I said, pretty sure I knew what was coming and relieved that he was going to ask.
"Is he blind?" the man asked.
"Yes," I said. The man said something about how he had thought so from the way Gareth behaved while they were playing.

How is it for you guys? For me, it was such a relief to have someone just say something rather than make Gareth's blindness the elephant in the room. I always waffle back and forth about whether to tell folks or not. My husband is in the let-them-figure- it-out-for-themselves camp. I usually lean more to just telling them straight out when they keep trying unsuccessfully to make eye contact with him. The other thing I struggle with is how to introduce my sighted child. When I'm telling people about my kids, I usually mention Gareth's blindness and then struggle with finding something interesting to mention about Theron. The reverse however also happens for me. I find myself telling people about Gareth's blindness and realizing that I'm making that out to be his defining feature--as if he doesn't have other things about him that are much more indicative of who he is. He's very demanding, whereas Theron is laid back. Gareth is curious (as is Theron) but much more cautious where Theron is a bull in a china cabinet. Gareth is much more physically affectionate. Theron is more quality time oriented. Do you guys notice this happening as well, or have you figured out new ways to approach it? How do you deal?