This is so bloody brilliant. I was thinking that one had no sense of privacy with respect to the civil service bureaucracy. But then there has to be a culture that would be accepting of such lack of privacy.
I'm kind of extrapolating from their slightly higher than normal acceptance of strangers that they are comfortable with their own restrictions. I would imagine that cultures where so much openness is forced on them would be more resentful of their lot in life and than in turn would lead to lower than normal acceptance of outsiders.
Their acceptance is only slightly higher, howerever, so I would guess that you probably have a fair number of things like 'teens in rebellion' where they refuse to wear symbols, wear the wrong symbols, or else do things to obfuscate their symbols and make them difficult to read in an effort to be 'cool'.
Like a vest with badges all over it, that would tell a story if you knew what all the badges represented.
I would think they would use something more overt such as badges if their society had a lower strangeness. They would still be heavily using symbols but it would be a simpler matter for people to learn what the symbols mean, hence not as strange.
Given their high strangeness I would imagine that the symbology is fairly difficult to learn. They might use badges, but their could still be a lot of context that makes reading the badges difficult (similar to how the letter c can have either a hard sound as in 'care', a soft sound as in 'cirrus', or a plosive when followed by an 'h' as in 'chair'. Same 'badge', different 'meanings').
Would this handicap Lemishians in dealing with outsiders? If everyone is, in effect, wearing their Facebook profiles on their chest, would that make them better or worse at reading outsiders?
If it did handicap them, the Lemishii would probably be less trusting of outsiders. It is even possible that older Lemishians could read people in a Sherlock Holmes kind of way.
It is possible it might hamper them, but I think it unlikely. For one thing the Lemishii are a bit more accepting of outsiders than the average. As you said if it handicapped them it would probably make them less trusting of outsiders.
Additionally the symbols can really only convey certain information. Dealing with people who are using the Lemish symbology would mean that lots of information that is normally exchanged during introductions gets immediately passed on when the Lemishii first meet without the need for verbal exchange. It wouldn't be able to pass along a lot of incidental information such as 'I'm a little sleepy right now' because if their symbology covered a lot of such variable bits of data then your average Lemishii would be in an almost constant dance of adjusting their clothing and whatnot as they become sleepy, hungry, happy, sad, etc.
I'm sure that the Lemishii probably also have to deal with the occasional 'liar' as well. Even if it would be absolutely against the rules of Lemish society to wear symbols that are deceitful there must be criminals among the Lemish, just as among any reasonably large sized group.
This isn't to say that a Lemishii wouldn't find it awkward living outside their culture in a land where no one 'speaks' their symbol language, but the awkwardness probably wouldn't be any greater than it would be for any other person removed from their culture and placed into a culture that they do not share close cultural connection to (i.e. they would probably have about the same difficulty as an American in a non-western European country). At least that's what I would think.