If a couple cops rolled up on me while I was armed with my Ar-15 or the like and I was on public or private land I would be concerned. Concerned enough to reach for the sky and do as told with a good attitude about it.
I would never cause harm to a police officer and I know that but I cant say a police officer would never do me any harm.
After all I would realize their not approaching to chat about how they like my gun and would like to check it out. I would assume they were called and then it becomes part of their duty to "check me out"
I know I would be nervous if a cop got out of his car with his shotgun in his hand because he pulled me over for speeding........like wise I can see where the cops would be nervous rolling up on a guy walking around with a AR......but it is part of their job. If they dont like it maybe they should find another line of work.