Ever since the attacks of 9/11 (2001) the Feds and Police have been telling EVERYONE to keep an eye out for anything that looks suspicious. A woman, in the desert, filming police helicopters might seem just a tad suspicious. I know it would strike me as odd.
And your above comment (which I quoted) is neglecting a few points.
1. Filming famous buildings also isn't illegal. It isn't even odd behavior if you're a tourist. It is, however, behavior that is watched for. By contrast a lone woman, in the desert, filming police copters IS rather odd.
2. No she probably didn't have to comply with a search or provide ID. At that point the Officer is fully within his rights to arrest her and "take her in" until the situation is sorted.
3. You know well that if she had been up to something illegal, or was a terrorist, and that cop didn't stop, you and everyone else would be all over him.
Suck it up. He didn't strip her and she was, in my opinion, being suspicious.