Conservatives blockading theaters would play right into Moore's hands. He'd love it. It'd just boost the controversy of the film, and he'd say conservatives try to supress free speech.
No, the best thing to do is to make voters aware of Moore's extremism and tie it around the necks of the Dems who have embraced him. Put up a TV ad, in South Dakota, for example, listing Moore's vicious anti-American quotes and then ask why Tom Daschle embraces and applauds this man, even to the point of delaying a vote on the defense budget to attend a screening of the film.
Excellent idea. From Terry McAuliffe and Tom Daschle on down, the 'Rats have lashed themselves to Moore's mast. They should be exposed for that and held accountable for every anti-American pro-terrorist statement he's uttered. Hopefully the Club for Growth or another group on our side will pick up on your idea.