Is Dan Brown an alien?

Now, I haven't read The Da Vinci Code. I started reading a copy of Digital Fortress I found in the bathroom but had to stop when Brown used the term "public sector" to mean "private sector".

I knew his command of English was bad, but I just read what is allegedly a quotation from The Da Vinci Code. It strikes me as almost impossible that the following sentence was written by an Earthican, whether born on Earth or merely naturalised:

"At the end of the corridor, illuminated signs bearing the international stick-figure symbols for toilets guided him through a maze-like series of dividers displaying Italian drawings and hiding the toilets from sight."