Way back when a prince was marrying his blushing bride at St. Paul's Cathedral, our OB truck was to provide the main coverage. Come the morning of the big day we had an 'everybody must attend' safety briefing. Our truck was parked on the far corner of a grass square, diagonally opposite the side door which was our way in. For the few days before we had been taking the direct route across the grass rather than the path round two sides of the rectangle. "On no account must you walk across the grass to go in to the cathedral," said the scary man doing the briefing. He explained that's what terrorists would do, take the direct route. "Anybody who steps off the path will be shot."
On a similar vein, Trooping the Colour during Northern Ireland 'troubles' brought similar arrangements. One summer little Stevie was given the job of getting the sound of the Queen's arrival at Horse Guards. "Right, so there are police snipers on those roofs and you want me to point this at the Queen? Okay." 'This' was a Sennheiser 816 gun mike in a Rycote windshield (non furry variety) with pistol grip.