He might have been a bomb! He might have been active and alive, most of the time... Security has been neglected at a time of the 'War on terror'. Fake war! The Monarch of England cannot be a muslim. Yet has not been a subject of threats since this mess began.
Broadly, the art of concealment has given rise to marvellous tales of crouching in a trench metres away from the target. Reality has proven them feasible.