I haven't (as of yet) carried anywhere that was off limits. I had to leave the gun in the car before going into DMV, because I have seen cops in there before as security(there wasn't any there that day), plus I needed to use my CHP as proof of residency and didn't want them asking,"do you have it on you now?"
Anyways, I'm not worried about carrying at a posted buisness. They can just ask me to leave. Not too worried about post offices or federally owned parks either. Courthouses and government buildings I don't think I would.
But who knows! An ex bosses' wife was grazed by a bullet when that nutcase shot 2 police officers in the US capitol building 10 years or so ago. So unless there's pat downs or metal detectors maybe I should re-think. This is just theoretically speaking,of course.