They had already talked to the cemetery and set up the visit and the rules were given to him (or his handlers) at that time. He (they ) were told it was just to be a personal visit with whatever handlers he required (ex.- secret service) but that campaign staff and photos/video was strictly forbidden. So him showing up with his campaign posse looking to do a photo op was something they already knew ahead of time was not allowed.

Edit - curse you autocorrect!