Visible crew/equipment: At the end of the Quidditch match, when Ron shouts, "Woo hoo!" with his arms raised, just as his cape flaps around the black seat on the actor's broom becomes visible. There are a couple of other quick glimpses of a seat during the Quidditch match. (01:38:45)
Visible crew/equipment: When Slughorn stands before Tom Riddle speaking of seven Horcruxes, as the professor faces the fireplace and says, "This is all hypothetical," and when Tom replies, "It'll be our little secret," in these close-ups particularly the square lighting/reflector screen becomes clearly reflected in their eyes.
Visible crew/equipment: When Harry is lying outside the hut at the end of the film, Snape kicks his wand away. A block of neon tape can be seen briefly beneath the wand when Snape kicks it.
Answer: Leaving an untrained young wizard, who obviously has some behavioral issues and has no idea he is magical, alone in the Muggle world would be extremely dangerous. Dumbledore does not yet know that Riddle will become evil, but like any teacher, he wants to give a troubled youth an opportunity to find a new path in life.
raywest ★