In 'Harry Potter and the Deathly Hallows' how did Stanley Shunpike know the real Harry Potter?

Answer 1

In the third book, Harry Potter and the Prisoner of Azkaban, Harry met Stan while riding the Knight Bus. In the book, Harry originally told Stan that his name was 'Neville Longbottom', but at the end of the ride on the Knight Bus, Hagrid calls Harry by his name, and Stan realizes that he just spent an entire bus ride with Harry Potter.

In the Deathly Hallows it isn't Stan who realises but one of the death eaters. They know because Harry doesn't knock Stan off his broom, just disarms him. He is the only one who would do that under pressure just because he isn't a death eater.

because harry is the only one who uses expelliarmus. the order of the phoenix wouldn't use that

All good answers but, there is one big reason you guys are all missing. If you read the 4th book, Goblet Of Fire, you should have read about the cup being a port key to a graveyard. Right, so during that battle, Harry used Expelliamus then the death eaters knew that even under pressure Harry Potter doesn't like to kill rather then to disarm or hurt. They then assume Expelliamus is Harry's signature spell. So when he uses it under pressure again, Stan Shunpike, the Knight Bus Conductor, knew it was the real Harry Potter