I can almost understand this. School crossing. Pedestrian crossing. Why wouldn't one's initial response be that "Deer Crossing" is much the same? And we all have a coupla dozen things tucked away in our knowledge base that we believe, but if we looked at suspiciously for a minute or two would toss out. My eldest, who is a smart man, recently posted on Facebook that it had just occurred to him what UCLA stood for. Sometimes we just don't look closely.
And yet...this seems a bridge too far. If you are seeing these signs all the time, giving them your attention, and getting worked up enough to start writing letters to the newspaper and calling radio stations, shouldn't it be a basic point...
Aw, screw it. She's just stupid. What do you think when you see the sign "Falling Rocks," or "High Winds?" The state did that on purpose? Too much precedent for her not to know.