Sometimes one sees something on the ground that looks special, only to find on checking that someone has discarded a candy wrapper. Another example is the crafted pictures that can be interpreted in two ways, as very different portraits.
I had a similar sense of ambiguity in seeing this sign. This is verbal meaning ambiguity, partly a result of the plate being the same design as other street signs in the area. The two possibilities overlap like the superposition of quantum states. In the shadows is also the question of what is private anymore?