ISPS requires that certain spaces are registered as Restricted, which does not mean that they are off limits to all personnel. Restricted means that the area is verifiably secure and so paper seals and plastic seals, which can be seen to be secure without restricting access in the case of an emergency and which identify if they have been tampered with, are perfectly acceptable. In the interest of safety, access should not be padlocked unless specifically required to be. Click on the image to enlarge.