Regarding the debate over Constitutionality vs Private Property Rights, the real issue is respect and judgement.
If the gummint doesn't respect the Constitution, then F the gummint & I'll do what I have to do be & feel safe. Carrying through a metal detector into a courthouse may be a fine way to "I'll show them!" However, it's also a fine example of really poor judgement.
Carrying in someone else's home or business, I'll keep my mouth shut. It they ask (in a home), I'll deny and find some reason to leave. That way, I respect their wish to be defenseless, maintain my own safety, and don't have a gossipy neighbor (or whatever) faceblarting "You know he has a gun on him, don't you??!!", thus making me a potential target for future harrassment, etc.
Decide where you stand, then exercise good judgement in carrying out your decision.
I understand the denial and then leaving. Not bringing more attention to the fact you carry is always my approach but for some relationships and situations denying might not be possible. I agree 100% sound good judgment and understanding of the situation is paramount.