Win $1 Million for Voting in Arizona

According to the Arizona Daily Star (HT Drudge), Arizona voters will vote on a ballot proposition that would establish a $1 million lottery for actual voters - that is, if you vote you are automatically entered in the lottery.

There is a history of poll taxes (declared unconstitutional by the U.S. Supreme Court) that once made voting an expensive proposition.

This sounds like an issue ready-made for Democrats - people who tend to vote Democratic have lower turnout statistics.

But I wonder if a court would consider it to be illegal vote buying?

UPDATE: The New York Times is reporting on this story this morning and raising the question of illegal vote buying.