So, how do you determine what a "freebie" outlet is?
I determine it by the nature of the outlet and by asking the owners, when possible. Some outlets are there to be used by the public. I have asked in many cafes and airports and the answer has been always the same: "of course you can use the outlet; that's what it is for!" Usually the answer comes with that "what an idiot" face.
After a discussion at elmoto.net, I even asked in the local national park if I could plug in an electric motorcycle in one of the picnic outlets and the answer was the same (you have to pay $15 to enter the park, so I guess is a "built-in fee"). I imagine that, when I have an elmoto that can actually cross the park, I will simply leave an extra tip in the donation box, but I see a lot of people plugging in even some fancy electric grills and nobody has a problem with it.
I have also asked at local gas stations and most of them say that, as long as I buy something in the store, I am a customer and entitled to use the outlet. Pretty much like the cafes and restaurants. Others just said "sure!" I don't know if the answer will be the same when I actually show up with the motorcycle and a long cable, but it seems common sense that they wouldn't change their answer, especially if I am consuming something.
in government buildings, I will just go for it. Even if they wouldn't allow it, I see it as my form of protesting the fact that Virginia has no incentives for electric vehicles, so I will create my own "after-the-fact incentive." Robin Hood style.