Access failures are predictable and therefore preventable
Almost every after-hours access problem falls into one of a few categories. A card is issued but not activated for the required zones. The alarm has a separate code from the door system and nobody mentioned it. The service lift stops running at a certain hour. The dock is locked and the alternative entrance has no card reader. Each of these is knowable in advance, and each will cost a full attendance if it is discovered on the first night instead.
The plan therefore includes an access test before the start date wherever a building permits it. A supervisor attends at the scheduled hour, uses the actual card at the actual doors, and confirms the alarm sequence. It takes an hour and removes the single largest source of early-contract failure. Where a test is not possible, the plan at least records a contact who can be reached at that hour and what they are authorised to do.
