[anigbrowl]

The above should not be downvoted. True, a sign is not the same as a verbal request for permission, but in general the display or frontage of a store is an invitation to examine the goods inside, and by crossing the threshold you are accepting that invitation - and by extension, the terms and conditions set by the owner of the private property you are stepping into.

A printed notification at the entrance of a property or event is the norm, and legally sufficient. In commercial video/TV production posting them is a standard pre-show requirement, to avoid lawsuits from people claiming their right of publicity was infringed. The current mania for blurring out logos and anything even vaguely offensive on TV is to avoid frivolous but legally expensive lawsuit threats from brandholders or obscenity investigations from the FCC, which can be triggered by as few as 50 complaints.