I'm sure this is old news to people who have been following this since the beginning, but I just came across it today. Over the seven and a half years prior to the shooting, Zimmerman made 46 separate calls to the local police 911 and non-emergency lines. In those calls, he reported a wide variety of things, from loud parties and dangerous drivers, to open garage doors, and children playing in the street.
Every call is documented, and those documents were made public by the local police:
http://www.documentcloud.org/documen...l-history.html
It seems like he's hyper-vigilant nearly to the point of paranoia.