Nancy Kelly and Kenji Yamamoto’s documentary is hereby recommended for anyone who’s ever crossed the Golden Gate Bridge going north and nearly wept with gratitude for whatever blessed benediction has allowed all those gorgeous rolling acres to remain unmolested. As Rebels With a Cause reveals, your fealty is due not to gods but to a sort of ragtag special-ops team of conservation activists, whose gutsy decades-spanning crusade has kept the Point Reyes National Seashore and Golden Gate National Recreation Area perpetually safe from urban development. True, it’s perpetual also in the sense that nobody will ever again be able to afford a house in Marin County anyway, but this seems a reasonable price to pay for maintaining the good health of what one participant describes as “the lungs of the Bay Area.” With the occasional gently scolding don’t-take-this-stuff-for-granted music cue, and some eloquently earthy narration by Frances McDormand, the film has the air of a museum exhibit informational video; it’s a tad too easy to tune out, but a comfort nonetheless. Kelly and Yamamoto responsibly carve their way through dense thickets of local and national political history, revealing how far we’ve come since the time when some people thought conservationists a scourge worse than communists. Eventually some brave citizens told the planned “Marincello” headlands development to go take a hike, and now, breathing ever deeply, we all can do likewise.