This time I see the name Thieves , and I immediately think it is more daring that Pirate.
It's a reference to one of my favorite movies about a man wrongly persecuted, and how he prevails, The Shawshank Redemption. The phrase itself merely means "loyal".
Love that movie. Funny - I thought of it since it was referenced in the movie, but I had no idea that's where you took it from. We'll call you Andy Dufresne from now on.