They're probably looking for fields full of weed or growhouses rather than your 4 little pots.
You probably have more to worry about from nosy neighbors and roaming utility workers.

If they're flying low enough for you to see the call letters on the 'copters, you can find out what they are.
We had one practically buzzing our house - it circled 4 times really low so I got a good look at the letters/numbers & looked it up online.
It was a Medi-Vac from the next town over - even found a picture of it that matched.

(I know it's hard not to be a little paranoid when you're in the middle of a grow so no worries.)

Good going on the chocolate ice cream smell - do you know what kind of plant it is?
I know some say they smell like chocolate with a touch of vanilla - just wondering if it's one that I know about.