All good questions and a very common problem.
Even fewer places have a process in place to verify the identity of the phone guy that shows up. If someone shows up who is dressed like the “phone guy” most places will simply let him right in. I have only seen one or two place that check a photo ID, company ID and call the phone company to verify the identity of the tech. Granted this is a lot of work but once you let someone into a comm closet you are basically giving them the keys to kingdom.