The problem you had is an over zealous turtle volunteer. If they didn't show proper ID, I would not have let them in my door. Probably not even with, come to think of it. You now what you had bought and it was none of their business.
My biggest concern is that someone was able to get your address via your vehicle tag. If the person that came to your door was not a LEO, then there has been a violation punishable by jail for giving out that information. I know this because I used to be a supervisor of a SO communications center.
I love the turtles and admire the people who take care of them but they shouldn't, if they did, barge into your home.
Please do not target the Turtle Walkers. (Bold italics above is mine)This was not one of them. All Turtle Walkers either wear a white or a blue shirt and it states South Walton Turtle Watch Volunteer right on it. I know because I'm one of them. The person who showed up in a brown shirt leads me to think Fish and Wildlife. They were on the beach on a 4-wheeler this morning while we were moving a Loggerhead nest and that guy wears a brown shirt. The shirt also has a badge on it.
You're very right to be upset about someone barging in like they did. Please let us all know what you find out as you track this further. I welcome any questions you may have about the turtle walkers that could help quell any doubts you may have about them.