I amended my comment about being law-abiding, but jeeze louise...
I don't think about my firearm all the time and don't have scouting forays to go and check for signage, and SURE if there was a HYOOUGE sign 'no guns or we'll shoot you' on the door, I'd go elsewhere.
Same way I don't call up a business and say "I'm coming over is it legal to walk on your grass or do I have to use the sidewalk". OBVIOUSLY if I'm at a public shrine and it says 'don't walk on the grass I will use the sidewalk', but the business may have little signs stuck in front and you have to walk on the grass to get close enough to see them.
I bet some of you 'goodie-two-shoes' who natter about 'law abiding' on OCDO chew tobacco and spit it on the sidewalk and throw your cigs out the window.
I don't speed, I don't litter, I don't cuss, I don't drink or smoke, I go to church, I have not harmed an animal since I was 12 years old, I don't steal or cheat, pay my taxes, I've never harmed another person besides sanctioned fights and sparring in the gym, never beat my child or my spouse, I don't owe any money (besides my daughter's school loan), no credit card debt, had two moving violations in 45 years of driving (last one in the 80s and the cop lied because I had cruise control on 55mph, the other was driving though a bank parking lot and 'avoiding' a traffic light...)), and I don't break the law INTENTIONALLY.
If your mother was in the hospital dying and you were CCing and the building was posted and nowhere to put your firearm, would you REALLY stand outside and let her die alone? HECK NO. So it's all about what you'll tolerate.
Me, I don't tolerate disarming myself and keeping a running spreadsheet about where I can carry, which signs are legal, which are not, if every door has to have one or not. If there's a Federal building or a metal detector, then I disarm. Otherwise, and partly due to my being nearsighted, I'm not scouring the countryside or buildings for little signs. I saw one when I came out of a store the other day - it was minuscule.
I bet EVERY single one of you has carried in a place they knew was illegal/signed once (or more). So if anyone is more saintly and law-abiding than me, I'd like to meet you.