Some of the buzz during the Professional Convention Management Association’s Convening Leaders conference earlier this month touched on an upcoming decision that could be either a boon or a bane for the San Diego meetings industry and the thriving restaurant, retail, and entertainment district it supports.

The decision has to do with a possible doubling of the San Diego Convention Center.

The SDCC was the an important part of a wholesale revamp of San Diego’s Gaslamp Quarter. The area’s vibrancy has attracted an estimated 60,000 residents to live in a single square mile of downtown apartments and condos. The SDCC estimates that it already turns away $1 billion a year in potential business due to limited space. The facility’s biggest annual event, Comic-Con International, continues to grow, and the race to expand among convention destinations ensures that the meeting will move if San Diego can’t accommodate it. At first glance, it’s an open-and-shut case.

Or is it? A report in the Wall Street Journal (subscription required for full text) points to convention center expansions in a half-dozen U.S. cities, from Boston and Chicago to Austin and Dallas, where occupancy fell far short of expectations. Partly due to long lead times, facilities like the Vancouver Convention Centre—my all-time favorite for a facility its size, with a gorgeous, LEED-certified expansion—are seeing occupancy drops driven by the economic crash of 2008. But that hasn’t stopped cities like New York, where plans are afoot to replace the Jacob Javits Center with a 3.8 million-square-foot venue, the biggest in the U.S.

Bookings will recover from the depths of the crash, just as they have with shorter-term sales. But in the hallways at PCMA, I heard a growing consensus that they’ll never return to historic highs. With the hip, happening cartoon fans who attend Comic-Con, I wonder how quickly hybrid meeting options, plus the cost and sheer hassle of air travel, will begin eating into on-site registrations. San Diego may already have asked that question, and Comic-Con may have answered it. If not, they’d better.

Roger Rickard, the doggedly effective advocate for face-to-face meetings, notes that the industry’s critics rarely acknowledge the local economic impact that flows from a major convention. He’s right, but he’s also feeding the critics’ case: If Chicago’s McCormick West is operating at only 55 percent capacity, it’s attracting meetings and generating local jobs and taxes, but not at the pace that justified the original investment.

Which means the answer to whether a facility expansion makes sense, in San Diego or anywhere else, is somewhere between “it depends” and “it’s complicated.” In some communities at some times, a project will be worth the investment. But with public funds in short supply and critics asking some good questions, it’s never been more important for the industry to get its analysis right, rather than assuming that every expansion is an automatic winner.

Coming up: On February 2, I’m moderating a webinar on small meeting design, featuring Adrian Segar, creator of the Conferences That Work model of participant-driven events. MeetingsNet’s Sue Hatch interviewed Adrian late last year, and we’ve summarized the interview and the webinar theme on our blog.

Mitchell Beer, CMM, is president of The Conference Publishers Inc., Ottawa, one of the world’s leading specialists in capturing and repurposing conference content, and founding chair of the GMIC Sustainable Meetings Foundation. Beer blogs at http://theconferencepublishers.com/blog and tweets as @mitchellbeer.