Yeah, I'll call BS about the stadium never being rented out. If that were true, then why have it on their site? Duh!
http://www.gohuskies.com/ViewArticle.dbml?DB_OEM_ID=30200&ATCLID=208588960
Also, Husky stadium has already been renovated. It completed last summer.
http://www.huskystadium.com/renovation-information/project-overview/project-timeline
As for cruise ships coming in, that may or may not be true. Cruise ships do drop off tons of people in Seattle. Whether they stay on the boat or not is not something I can confirm.
In-city hotels in Seattle are like any other large city... expensive. Sheraton, for example starts at $285 per night (I just checked the normal rate for that weekend). But many of the hotels on the list are outside of Seattle and are significantly less expensive, especially when you get down into the more "economy" brands. The city of Seattle and the upscale Bellevue area will command more money. And $140 per night is actually about right unless you get to those more "economy" brands. Although on that weekend, one of the economy brands was pretty expensive when I looked just now, but other brands were significantly less ($125 and $80 for two I just looked at online). And if someone were to stay near the airport, those rates would be in that range normally.