Left to Harry by his father, he was unaware of its true origins, or indeed its true powers, and it was used largely in order to travel around the castle and grounds unseen, including trips to Hogsmeade when his lack of a permission slip meant he was banned from the visits.

In Harry Potter and the Prisoner of Azkaban, Harry was banned from visiting the village of Hogsmeade because he did not have a signed permission slip from a parent or legal guardian. His uncle, Vernon Dursley, refused to sign the form after Harry accidentally "inflated" Aunt Marge during a fit of rage and ran away from home. Despite Harry's pleas, Professor McGonagall strictly upheld the school rule that third-year students without parental consent could not leave the castle grounds. Additionally, the Ministry of Magic and Professor Dumbledore were concerned for Harry's safety, as the notorious prisoner Sirius Black was believed to be hunting Harry and had been spotted near the school. Later, in his fifth year, Professor Umbridge also revoked Harry's Hogsmeade privileges as part of her "Educational Decrees" to punish him for telling the truth about Voldemort's return.