From the Nightstalkers' homepage, two commandments of OpSec:
I. Thou shalt not park thy helicopter in the open, for it bringeth the rain of steel.
X. Thou shalt cover thy face, hands, and helmet, for thine enemies maketh war not on bushes.
More available at
www.nightstalkers.com
Also from the same source:
The important things are always simple.
The simple things are always hard.
The easy way is always mined.
If the enemy is in range, SO ARE YOU.
Anything you do can get you shot, including doing nothing.
And last, my favorite:
"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." ~George Orwell