TexasCHLforum.com

I think Ruark was talking about lines at concerts, etc. where they do bag checks when you go in, not Walmart type security.

Actually, oral notification can be given by anyone in authority to provide that notice. In other words, if a person has been given permission to ask you to leave the premises, then you must leave. This can include employees, grounds-keepers, janitors, etc. So, if I was at a location and told by anyone that I was not allowed to carry there, then I would retreat until I could find out for sure if they were authorized and wouldn't risk getting charged with criminal trespass for not leaving.

But, as others have said, concealed is concealed and if you do it right, then they shouldn't know you are carrying, and absent of written notification being there, then you wouldn't get notification.