That was then, during a war, a real war, where everyone in London was in danger. No way in hell her current bodyguards would let her go somewhere if they actually thought there was a decent chance of a bombing. Their bravery during WW2 served a purpose. Her murder by terrorists today would be a tragic disaster, to be avoided at all costs, the 70th anniversary of V-J day is not so important to anyone that they would genuinely risk the life of the Queen.
They don't get a choice. The Queen gives the orders on this, and they are obeyed. Her bodyguards may advise her, but they cannot force her.
In 1981, somebody fired blank rounds at the Queen during the Trooping of the Colour - but nobody knew they were blank rounds at the time. While soldiers rode forward from parade to surround her, she was not evacuated, her bodyguards stayed back, and she continued the ceremonies after calming her horse.
I was about twenty yards away when somebody fired shots (again blanks) at the Prince of Wales in 1994. In his case, his bodyguard did put himself between the gunman and the Prince, but once the man was restrained everything just went on as normal.
They accept these risks as part of the job. They will not allow them to stop them doing their job.
Their bravery during WW2 served a purpose. Her murder by terrorists today would be a tragic disaster, to be avoided at all costs, the 70th anniversary of V-J day is not so important to anyone that they would genuinely risk the life of the Queen.
I think the Queen would say that if she didn't attend such a ceremony out of fear, it would be giving into the terrorists. Yes, her assassination would be a tragedy for her nation, and personally for her - but the Crown would continue.
Notably, the Prince of Wales was not present (instead attending a different commemoration), when I normally would have expected him to be - it's quite likely that was the precaution being taken to preserve the succession in case something happened.