It doesn't seem like a language issue, but a user error. One person with a lot of knowledge about MIT says to someone with no knowledge of MIT "Go to the Green

It doesn't seem like a language issue, but a user error. One person with a lot of knowledge about MIT says to someone with no knowledge of MIT "Go to the Green Building" with no further context, that's on them. Likewise, if you're told to go to the Green building, look around and nothing immediately jumps out, you'd ask for directions, or an address, i.e. a unique identifier that sort of transcends language. "Ah, building 54, thanks". (And let's not discount that maybe the person talking about the Green Building might be unaware of the green building, or even colorblind) People can be obtuse to show off insider knowledge. Readers can find stuff for which they weren't the intended audience (which is very common post Internet). However, it is important that it seems like even when there's a complete lack of context around the improper noun, our brains are good at understanding that the phrase might mean something else, and we can choose to look it up or not be bothered. I'm not sure if any more signifier is needed. Writers might not even know they're using an improper noun, afterall.