I don't know if people spot me as someone on the spectrum. I never managed to blend in though... but that's more of a personal preference. fashion sense and then some, that puts me more outside the norm to start with.
As for the rather blank aspie stare... I think I have it quite a lot, but I wear shades pretty much all the time (except when I'm at home) so I don't really have the eye contact issue that much, as well as not having a stare going on that people notice. However, I wear those shades for a different reason than those mentioned.
Except for a small group (mostly the people here) I don't really express my (sensory) issues as well. It's not that I dont want people to know, but it's more of a "I rarely talk to people". On a regular week I talk to 4 people in real life, one being my girlfriend, who is aware of it, the other a friend, who is on the spectrum himself, and the other 2 are my parents, and I don't really talk a lot to them to start with.
So, all in all... I think the idea people get from me when I'm outside is that I'm a bit peculiar anyway and that my Aspergers might be the least bit "weird" I show off. I'm quite sure if you were to talk a lot away from me in sense of how I dress, things I prefer and put me in the more accepted mold, then my Aspergers will show more. That's also for instance where school and work interfered, because they thought my... erm... "persona" (the combination of how I look, dress, talk, think and act) was a facade, but in the end even therapists found out that I'm "like that in any and every sense" and changing it would be a really weird (or even dangerous) thing to go for in my case... since, and I read about this in my old reports from therapists in my teens... I was classified as having an identitydisorder of sorts, they just never conclude why and how... I think I know why and how... it's because, as a teen I was expected to act "like everyone else" and that just didn't sit well with me... in any sense.
So that concludes the "how can they spot us?" on my part; People will probably spot me as someone who is "different" but they have no clue what exactly my issue/disorder might be. And after close inspection people thought it went from disassociative personality disorders to bipolar, but never autism. For a big part I'm not THAT insecure as a lot of people on the spectrum are. Yes, I have my share of awkward moments, but I have my moments where I have a lot of confidence as well... I can easily steamroll someone in a conversation (if I want/need to). A while ago someone even asked me if being a public speaker would be a job for me... me? public speaker? meh... I'm well aware of my verbal capabilities, but I'm also well aware that I cannot function within a set of rules and my problem solving skills are more towards a lateral thinking perspective, which might be more attributed to the autism spectrum.
Looking at the start at the previous paragraph... "so that concludes..." and I still ramble on... my inner voice is telling me outer voice to shut up for now.