Simplificando, porque Vernon não lhe deu uma chance. No livro, ele puxa Harry para fora da sala antes que ele tenha uma chance de pegar uma única letra, muito menos várias:
Something came whizzing down the kitchen chimney as he spoke and caught him sharply on the back of the head. Next moment, thirty or forty letters came pelting out of the fireplace like bullets. The Dursleys ducked, but Harry leapt into the air trying to catch one – “Out! OUT!”
Uncle Vernon seized Harry around the waist and threw him into the hall. When Aunt Petunia and Dudley had run out with their arms over their faces, Uncle Vernon slammed the door shut. They could hear the letters still streaming into the room, bouncing off the walls and floor.
“That does it,” said Uncle Vernon, trying to speak calmly but pulling great tufts out of his moustache at the same time. “I want you all back here in five minutes, ready to leave. We’re going away. Just pack some clothes. No arguments!”
— Philosopher's Stone, chapter 3 (The Letters From No One)
Talvez Harry pudesse ter escapado de um deles enquanto deveria estar fazendo as malas, mas Vernon teria visto isso enquanto arrastava Harry para fora do quarto. Uma vez que eles estão lotados e saem da Rua dos Alfeneiros, Tio Vernon fica de olho em Harry que ele não tem a chance de pegar uma carta e escondê-la até que ele possa ler em privacidade.