I think the Indian casinos east of Sacramento (Thunder Valley on I-80, Red Hawk on U.S. 50) have had a significant effect on the bottom line of the Tahoe and Reno casinos. The last time I was on the north shore of Tahoe, late last summer, I went into the Hyatt Regency in Incline Village and was the only person gambling in the entire casino on a Wednesday afternoon. And the Hyatt is usually the busiest of the north shore's casinos. You could shoot a cannon through the Tahoe Biltmore most days and not hit anyone, and as Frank mentioned, the Cal-Neva has had problems. I really like the Crystal Bay Club - its owner, Roger Norman, is a chip collector - but it's rarely busy, either.
I'll be there in two weeks and don't anticipate any difficulties with crowds.