Daft rule introduced with little apparent insight to the business of security.
The irony is that on my current type (EMB 145) with the jump seat occupied univited visits to the flight deck are impossible..it blocks the door.
This is even acknowledged by the company who advise, in the event of hijack and serious disruption in the Cabin deploy the jumpseat to protect the cockpit !!!
flippin bonkers the lot of em .