One would think, from the Feb. 16 pep rally that was the press conference to announce the new arena proposal, that a third sports stadium in SODO, for basketball and hockey, was a slam-dunk.

Though King County Executive Dow Constantine assured, “This is not Game 7. This is the tip-off to the first game of the preseason,” he and Mayor Mike McGinn appeared a little too enthusiastic over a proposal that was deemed “not serious” in the media in recent weeks. There even seemed to be a cheering squad that applauded and shouted at appropriate times.

Indeed, Constantine is correct when he said this was just the start — of something that is too good to be true. With the help of McGinn since last June, the arena proposal answers all of the public’s possible concerns about private funding and construction-cost overruns, even the future of KeyArena.

Roosevelt High School graduate and San Francisco hedge-fund manager Christopher Hansen, who submitted the proposal, has already purchased the property to the immediate south of Safeco Field’s parking garage for the future stadium.

And a Rainbow Coalition of sorts has already formed with 10 advisory-panel members in place — including Urban

Visions founder and CEO Greg Smith, Seattle Community Colleges chancellor Jill Wakefield and El Centro de la Raza executive director Estela Ortega — tasked with submitting a report next month.

There’s also been talk that a pro-basketball team could play in KeyArena starting this fall while the new stadium is built — despite requiring a bond measure that voters would need to approve before any construction could start.

Then there was the campaign promise of the new arena spurring Seattle’s economy with thousands of construction jobs and millions in tourists’ dollars — not something a city or county leader would tout without further study unless they were already pushing for voter approval.

There’s no doubt Hansen’s $500 million proposal has been put on the fast track — McGinn even mentioned the similarly fast-tracked Chihuly glass museum at Seattle Center. But there are too many factors Constantine and McGinn hope Seattleites will ignore.

NBA commissioner David Stern thrives on his “blackmail economy” of forcing one city to make financial sacrifices for new arenas while dangling another city along. It’s how Seattle lost the SuperSonics in the first place.

The National Hockey League would sooner put a team back in Quebec City, which had a team until it was forced to move to Denver in 1995, despite having a huge fan base. Seattle didn’t have enough support to keep its junior hockey team from moving to a new, smaller stadium in Kent.

Seattle’s economy is nothing like the cities that have built similarly funded sports arenas. While those cities, like Denver, weren’t hit as hard by the nation’s failing economy, Seattle will likely take years to recover, and a new sports arena isn’t going to stop more budget cuts from happening.

With the way this arena proposal has been pushed and pushed through, expect to see hidden costs surface — and learn what these politicians’ real priorities are: to get box seats and have their names on the side of the arena.