I can usually (about 98% of the time) pick up on the assumed context. I recognise that not everyone does, so I try not to make the assumption. For me that goes back to the curse of knowledge problem more than anything. It makes sense to me because I know the context and underlying information about the matter. I try not to make an assumption that everyone will know that when reading my notes/emails/documentation/etc.

Native English speakers use affect and effect fairly interchangeably, so most don't know the difference because they haven't opened dictionary.com in a decade or more.