Vancouver has a higher average attendance than both Seattle Sounders and Toronto Lynx when both were in A-League/USL1. With MLS coming, attendance should rise to near Seattle levels once hockey season is over. The original NASL Whitecaps averaged over 20,000 in their later years in the late-70s and early 80s. They also had over 100,000 fans show up to their victory parade after winning the 1979 Championship.
http://www.youtube.com/watch?v=b6dGbAFdOJQ
Vancouver is a hockey town and the Canucks, for most, are the only game in town until playoffs are over (foreign concept in Toronto I know). Had last night's game been played on a weekend and on a night when the Canucks weren't playing 2nd round home playoff game there's no doubt Swangard would've been a packed house.