Actually the officer was quite cool. I fly a lot in a subdivision that has never been built beyond just the roads - huge open field. Anyway right at the end of my second flight he drives all the way over to me, rolls down his window and says "what's going on?"
I told him - I'm just flying my quad-copter. He says "good place to do that... just had to check to see why some guy is on vacant land... have fun"
I thought he handled it with all class - and I find if you don't get pushy - the sheriff isn't out to ruin anyone's day