An article in The Sun (warning: there is nudity contained in the link), claims that two streakers disrupted production of Harry Potter and the Half-Blood Prince on-location in England.

Two male streakers held up filming of the new Harry Potter movie � by darting naked through undergrowth during a woodland scene.
Stars Daniel Radcliffe and Helena Bonham Carter retreated to their caravans while security chased the pair off.
But once filming resumed on The Deathly Hallows, the duo crept back and made monkey noises at the location shoot in Farnham, Surrey.
A source said: “Seeing naked bodies was a laugh � but the joke wore thin.”

This is unverified by WB, but still very amusing I must say.

Thanks TLC!