> where did you get that idea from?
From the fact that it actually happened.
It may not be "policy" but that doesn't mean it can't happen. One mistake leads to another.
First mistake (by a manager): worker is asked to work on the grocery till (maybe because queues are long, and presumably forgetting that the worker shouldn't be asked to work there)
Second mistake (by the worker): worker agrees to work on the grocery till (presumably trying to be helpful, and hoping desperately that no customer will present pork or alcohol)
The outcome of these two mistakes, plus the "policy", is the ridiculous situation that a customer can be refused service to buy a legal product that the store chooses to sell and the customer chooses to buy.
This is an outcome of the policy. It may not BE the policy itself, but it is definitely an outcome of it.