3201 Woodland Dr. NW
This is from June 2011, before they did the renovations. Wonder if they installed a new system at that time.
I don't know that houses in that neighborhood would stick a sign in their yard saying "Protected by..." It is assumed they have high tech security systems, and might be considered "tacky". I doubt DW targeted the S family because he thought they might not have a security system. If there was a sign, it obviously didn't deter him.