It wouldn't be in character for British street artist Banksy to reveal all, even in a film about his work--nor would it be legally prudent. Instead, the elusive stencil-master, face concealed via hoodie, shines a light on amateur documentarian Thierry Guetta. Based in Los Angeles, the French-born bon vivant films everything. On a trip to Paris, he follows his cousin Space Invader around as he affixes his video-game mosaics to walls throughout the city. As he says in retrospect, "I liked the danger." A vintage clothing shop proprietor, he decides he's found his new calling and returns to record other artists, like Shepard Fairey, who found fame through his Orwellian "Obey" image, which features André the Giant (Fairey later designed Obama's "Hope" portrait). Through Fairey, Guetta meets Banksy, whose visage remains a mystery. Guetta captures him in his studio, on the streets, and during preparations for his "Barely Legal" exhibit, at which Brad Pitt and Jude Law make appearances, but things fall apart after an ill-fated trip to Disneyland, where Banksy pulls a stunt that references Guantánamo Bay. Afterward, he encourages the videographer to mount his own show, which yields unexpected results. If it seems as if Banksy is making fun of Guetta, he mostly holds a mirror up to hipsters who'll fall for anything deemed cool (like this film). Narrated by Rhys Ifans, Exit preserves Banksy's anonymity while biting the hand that feeds--with wit and humor.