That's fascinating stuff, Guru. Many thanks for posting.
Seems to me then that if I wanted some general background shots inside shopping mall which was privately owned and had a sign up saying no photography I could simply shoot it
I might be spotted and asked to leave.
I would comply.
I could not be detained whilst a police officer is called (assuming one is not present).
I would leave the premisis without giving my name, address or any other details.
So, unless an employee follows me home, the owner has no details of me and cannot attempt to prosecute me for trespass.
Or have I missed something?