It's worth noting that last night on KCTS 9, Governor Christine Gregoire (who, unlike Paul Allen, will be voting in favor of levying an income tax on wealthy Washingtonians) directly addressed what is probably the biggest fear about I-1098.

How? She promised to veto any future effort by the state legislature to extend the income tax to people earning less than $200,000 a year.

Gregoire's statements, as transcribed by KCTS 9:

GREGOIRE: I’LL VOTE YES ON 1098
"You know, my hat goes off to Bill Gates, Sr., and I’m gonna vote yes... because I can't figure any other way to pay for education in the state of Washington other than what Bill Gates Sr.’s brought forward. And if we’re not willing to do this, then I fear the financial success of our children and our state if we’re really not going to really invest in their future through their education."

GREGOIRE: I’D VETO ANY ATTEMPT TO EXTEND HIGH INCOMES TAX
"The law, in order to change it, really would require a two-thirds majority vote to amend it or change it.... So I can’t assure you of anything, but I can tell you I would veto it as Governor. And I can tell you I don’t think it will ever arrive on my desk, because I don’t think there’s a legislature that would ever do it."