Tourists, while crucial to a country's economy, can oftentimes be a nuisance. Nowhere is this more apparent than in England, where members of the Idiot Brigade like to taunt the Queen's Guards, soldiers who keep watch over Her Majesty's residences.
There are plenty of videos showing tourists being reprimanded for heckling and/or touching the Guards. And yet, they continue to do it. The most recent example occurred at Windsor Castle, where a female tourist stepped over a rope meant to separate the Guards from the public. As she posed for a photo, the Guard on duty marched up behind her -- never breaking stride -- and shoved her out of the way.
Watch:
The rope is there for a reason. The Guard is not there for show. The Queen's Guards (or the King's, depending on who is monarch), are fully-trained soldiers. So when a tourist provokes a Guard, he will point his fully-loaded gun and shout, "Stand back from the Queen's Guard!" These soldiers have the backing of the British Army, so if you are the offending party and you're upset because you purposefully antagonized a member of Her Majesty's armed forces, any complaint you make will likely be ignored.
Don't tease the guards. It's obnoxious.