If "work" involves entering a secure facility, and there is viable concern that anyone entering the perimeter might be a terrorist or otherwise cause serious trouble, then YES (insofar as the bus just go around the facility, and only those having reason to enter be allowed in).
Were I facilities manager, letting the general public in via bus and then "securing" it by empty overtures of "checking ID" would NOT be tolerated. A secured facility should be just that: NOBODY ENTERS WITHOUT POSITIVE CONFIRMATION OF REASON TO BE THERE (to wit, every ID is checked against a list of authorized entrants).
I am all with you an that, it is permissable and reasonable to provide ID when entering certain restricted areas. It is the law in some cases. So, I don't know why all the hubbub. Again, she is a poor helpless granny, so the correct thing to do is ignore the larger picture and focus on this poor soul and her unfortunate travails and live vicariously through her so all (or some) here can spout out loud all the things they've memorized from reading the papers....