SVO, I agree with you, but...
... in the case I am describing, my issue wasn't with whether I should have been able to IGNORE the sign because it wasn't in accordance with spec.
My issue was what, if any, ramifications there would be when a sign is placed so that a person can very easily fail to see it in the first place. This sign was akin to a STOP sign, placed behind an inadequately pruned tree. IE, it was placed in such a way that the odds were high a person would never see it.
I didn't see it until we left. Neither did my lady. If either of us had, we'd have gone elsewhere.
But, if something had happened while we were there, what would have been the legal ramifications, given that the sign was placed so that it could not be seen very easily when entering the building?