There are some instances in the Harry Potter series where the muggles should have taken notice of the magic taking place before their eyes.
With the director of the first two Harry Potter movies, Chris Columbus, recently stating that he would like to adapt The Cursed Child (per Variety), fans are excited about the prospect of jumping back into the beloved world of the series. One of the most important aspects of that world is the separation of the Wizarding World from the muggle realm, with various tools and magical means used to conceal magic. Despite these tools, though, there are some instances in the Harry Potter saga where the muggles really should have taken notice of the mystical things taking place before their eyes but, for some reason or another, did not.
Of course, almost all of these situations can be put down to some sort of charm, spell, or magical concealment. Still, some examples are so glaring that even with all the magical tools available, someone, somewhere, should have realized what was going on.
When Harry inflates the insufferable Marjorie Dursley in The Prisoner Of Azkaban, one of the most book-accurate Harry Potter films, he is let off by the Minister for Magic for using underage magic, and a couple of Ministry workers received, deflated, and erased her memory.
Still, even if the witches or wizards were on the scene directly after the sequence is cut, someone, somewhere along Little Whinging, if not greater Surrey, should have noticed Aunt Marjorie and realized something was very wrong. At the very least, they would ask around about the inflated, screaming woman. The movies left out quite a bit about the Dursleys, but muggles coming across Marjorie does not appear to have happened at all.
The reasoning given by Stan Shunpike for muggles not seeing the Knight Bus is that they do not notice; they do not see what is in front of them because they never really look.
Nevertheless, someone really should have noticed something somewhere, particularly with all of its clanging and banging and the fact the Knight Bus is one of the most dangerous modes of transport in Harry Potter. Even with magical concealments, it seems unlikely that no muggle would ever go without hearing or seeing the bus.
One of the most iconic scenes in the first Harry Potter movie sees a barrage of owls fall upon Privet Drive to deliver Hogwarts acceptance letters to Harry. Alas, nobody seems to blink twice at such an occurrence.
Even if their minds do not immediately jump to the conclusion of magic, the amalgamation of owls surrounding the home of the Dursley's delivering letter after letter must have raised some alarm bells in people's heads about unnatural possibilities.
This is something that is explained away pretty well in the series. Ministry employees are on hand to erase/alter the memory of muggles who notice witches and wizards who go to Platform 9 3/4.
However, even with witches and wizards on hand, it seems wildly unlikely that groups of muggles do not notice people running through walls at a busy London train station and don't manage to evade capture long enough to spread the news around. After all, London's stations are notoriously busy, it would be easy for at least one muggle to slip away.
The first time audiences see Harry's magical ability is when he converses with a snake at the zoo, inadvertently freeing him from his enclosure by making the glass in front of him disappear.
People at the zoo, though, were far too focused on the snake to notice how it had escaped or how a young boy got trapped in the enclosure with the glass newly intact. There were no Ministry workers around to erase muggle memories, so people would have seen the spectacular and mistifying event unfold. Harry Potter features incredibly brave muggles, but it seems none of them were at the zoo to examine just what it was that happened with the snake and Dudley switching places.
The people of Privet Drive were an ignorant lot, and one of the biggest examples of this is when Harry leaves the Dursley's home from the last time, accompanied by older wizards and twelve other versions of himself.
How nobody took any notice of the goings-on at number four is bewildering. Between a half-giant in a magical motorbike to people riding brooms and Thestrals, the magical world was dealt to muggles in the surrounding area on a plate. All it would have taken was one nosy neighbor peering out of their window to see something going on, particularly as a battle then ensued right above them.
This is not to say that any muggle should have been able to find the Ministry of Magic - the organization would never allow that - but, at the very least, someone should have noticed something wrong with the peculiar entrance.
The underground toilets at Whitehall would see many, many people enter, and none return. A special token was required for Ministry members to enter the cubicles, but in a crowded place like Whitehall, for nobody to notice the abundance of people entering the cubicles only not come out again, at least not for the entire working day, is baffling.
Thestrals are some of the best-designed creatures in Harry Potter, and fans know that they can only be seen by those who have witnessed death. This narrows down the number of potential muggles who might have been able to glimpse the Thestrals themselves, but it's still a wonder that no one saw the flying children accompanying them.
Harry, Ron, Hermione, Luna, Ginny, and Neville all flew through the skies toward the Ministry of Magic, and yet, not a single Muggle in Britain saw this worrying sight. It is actually hard to choose between what would be a more bewildering sight, seeing six Thestrals transporting children through the air, or simply seeing the children alone.
St. Mungos is really not that well hidden, especially not compared to other magical institutes like the Ministry of Magic or Hogwarts. How nobody came across it or witnessed people enter it is almost unbelievable.
The hospital is located in a disused department store in London which is protected by a sign simply saying the store is closed - hardly enough to keep vandals or urban explorers out. In addition, nobody seemed to take notice of people speaking with a mannequin before entering the store, nor did they decide to try and follow them.
Plans to hunt for Horcruxes got accelerated when Death Eaters attacked the wedding of Fleur and Bill, and the Golden Trio are forced to apparate, right into Central London no less.
None of the tonnes of people in Picadilly Circus noticed. Clearly, these muggles were too busy with their hustling and bustling to take notice of three teenagers appearing from thin air in the middle of a busy London street, but it is hard to believe that not one muggle bore witness to the magic.
