Terribly dumb move, telling the police they aren't welcome.
Epic stupid. Let's say the restaurant IS robbed. The police can honestly say they were asked NOT to intervene. They can say there was actual confusion regarding whether or not they were allowed to do anything on behalf of the restaurant. And they'd have a decent argument. Honestly.
They were told they aren't welcome on the grounds. Does that mean they really shouldn't begin doing their "job" until the alleged perpetrator leaves the establishment? It's not like the police can actually come IN to the restaurant. They have to wait outside based on the wishes of the ownership. So... What if their shift ends?
Seriously, if I were the chief in that neighborhood, I'd let the guys know not to put themselves at unnecessary risk for that particular establishment. They are, after all, unwelcome.
**** that establishment. If they have a robbery, the cops shouldn't respond