Blame it on the city, or blame it the band, but last night in Seattle people did not freak out for the surprise “special guest” appearance of Death Cab For Cutie during the opening of Barsuk Records’ 15th anniversary weekend.

Instead, the 800 or so gathered inside the Showbox breathed a comfortable, rhapsodic sigh when the band walked onstage unannounced just before 10 PM. The assembled Barsuk faithful — flannelled and hoodied and mostly pushing 40 — were more accustomed to hometown Death Cab experiences of this scope than, say, the massive Key Arena, where the band played in early September.

For the uninitiated, Barsuk released DCFC’s first several records and EPs, from Something About Airplanes in 1998 to Transatlanticism in 2003. In the Seattle music world, Barsuk is kind of a stepkid to the more prestigious record label across town, but unlike Sub Pop, Barsuk has over the years remained completely independent of major-label involvement. Maybe bandleader Ben Gibbard related to Barsuk’s underdog status, because he and the label have retained close ties, socially and financially, even as Death Cab has moved on to a multi-album deal with Atlantic.

“I wouldn’t miss this for the world,” Gibbard said as the bandmembers took their places across the front lip of the stage. Saucer-eyed with evident joy, hair bowl-cut and bouncing, he looked like a grown-man Calvin sans Hobbes. He and guitarist Chris Walla both played acoustic guitars; bassist Nick Harmer switched between acoustic guitar and electric bass. To their right, Jason McGerr brushed a small, simple percussion set-up that Gibbard later referred to as “the cocktail kit.”

The acoustic format might’ve been a low-volume response to the relatively small venue. It also may have been a sign of deference to Nada Surf, the night’s official headliner. Either way, in acoustic mode, Death Cab’s set of eight Barsuk-era songs was loose and playful, almost casual. They traded the dramatic grandeur of their meticulous, festival-headlining sets for a more familial feel.

Beginning with “Steadier Footing” and going straight into “Photobooth,” old songs caught fans off guard in this new incarnation.

“Backstage Nick said to me, ‘This is like the best high-school reunion ever, where we actually love everybody and everybody looks beautiful,'” Gibbard said between songs.

The highlight of the short set came halfway through with “Pictures In An Exhibition” from Death Cab’s first album. Here they amplified the song’s mid-tempo grind to an almost-aggressive stomp, Walla pummeling his acoustic unreservedly and startling himself in the process.

“That felt authentic,” he said afterwards.

“Very ’98,” Gibbard retorted.

Among the crowd were a slew of Seattle music notables: David Bazan, Dave Terry of Aqueduct, Eric Elbogen of Say Hi, Shelby Earl. Barsuk Founder Josh Rosenfeld strode around the Showbox hand-shaking and shoulder-slapping.

Before closing with “The Sound Of Settling,” Gibbard took one final opportunity to express his gratitude to the label.

“Back when we played Key Arena this summer we talked about how much Barsuk meant to us, and it’s true — we wouldn’t be here if it weren’t for them,” he said. “We’re honored to be part of this celebration.”

The Barsuk Records’ 15th anniversary continues through Sunday at venues around Seattle. Upcoming headliners include the Long Winters, Ra Ra Riot, Phantogram, and Jesse Sykes & the Sweet Hereafter. All shows are sold out but recordings will be available next week via getlive.ly.