It's sucks to worry about your hard earned $$ out in the woods, but honestly...if someone wants something bad enough, they'll get it. Very sad, but true. The best you can do is lock it up using some type of cable system just to keep the honest people...a bit more honest.
This is what I'm using on my trail cams. But it still doesn't matter. If someone wanted it, they could just cut right through it.
http://cgi.ebay.com/1-NEW-Master-Lock-Python-Security-Lock_W0QQitemZ160035555404QQihZ006QQcategoryZ11896 QQssPageNameZWDVWQQrdZ1QQcmdZViewItem