Whenever you ask the managment, you force them to make a decision about something they probably hadn't thought of, and you put them on the spot. The person you are asking is under pressure to play it safe and tell you "no". He's more afraid of what his boss or his insurance company or his many non-OC customers will think than he is of what you might think.
If you just OC and act like a gentleman, they may see it and not bother to ask you about it. If none of the other customers say anything, why should they?
That is my take on it, anyway. Doesn't always hold true, of course, but as long as you're polite and you don't have some pre-knowledge of the owner's dislike for visible firearms it's not disrespectful to do this.