[dragonwriter]

> Wearing a bow tie in an informal setting broadcasts an unawareness of (or an uncaring for) social norms (specifically, the social norm that bow ties are formal wear).

Its actually not that at all. While "most men ... only wear bow ties with formal dress" is true, that is not because bow ties in general are formal dress. The specific forms of bow ties which are formal dress are not what the small minority of men who wear bow ties in other contexts generally wear. They wear forms that are understood (or were, when they were in fashion) as informal dress, which are quite distinct. They just aren't currently popular fashion.

[lisper]

> The specific forms of bow ties which are formal dress are not what the small minority of men who wear bow ties in other contexts generally wear.

Well yeah, sure, but that doesn't help the situation at all. Clowns, for example, wear bow ties informally, but that's not exactly the kind of image I would like scientists to associate themselves with either. Yes, there was a time when bow ties were fashionable as non-formal wear among non-clowns, but as you yourself point out, those days are long gone.