I haven't done this yet, as far as I remember. I've noticed a lot of things that I've done "wrong" because of AS, but I really wouldn't expect most people to understand what I was talking about, and I'd half expect them to conclude that I was just making excuses, so generally I wouldn't bother. It might be different if I knew anybody who was particularly interested and sympathetic to my condition, but apart from the folks here on WP, who don't have to deal with me in real time, I don't know anybody like that yet.
If my employer started gunning for me because of some AS-related problem, than I'd almost certainly blame AS in my defense, in order to protect my livelihood. Similarly, if I were under serious attack from anybody else because of my condition, I'd definitely consider explaining my behaviour in terms of AS. But it hasn't been necessary so far.
The reason I see it as a tool of last resort is that I find it really difficult to explain to others how AS affects my behaviour, especially if they're turning hostile, and like I said, I doubt that many of them would believe me or take the trouble to understand.
I did explain the condition to a couple of people when I was first diagnosed, but it seems to have had no effect on either of them. Luckily, neither of those people are any more powerful than I am - if they want to ignore what I've told them, then that's fine as long as they don't give me any crap, and if they do, then I guess I'll remind them that I tried to warn them that there are some expectations that can't realistically be applied to me....if that doesn't cut any ice, then to hell with them. It'd give me more time to find people who are a little more patient and caring. But I'm hopeful that it won't come ot that.
Anybody who's interested in my condition, I'm quite happy to try to explain it to them if they just ask. But I'm not likely to volunteer much unless there's a very pressing need.