Americans are just crazy about voting. And they don't seem to care about all the fancy election "rules" that govern where and when the votes happen. On Super Tuesday, voters showed up in Texas and Virginia to vote, apparently undeterred by the fact that no vote was scheduled to take place. In Florida, voters came to the polls to vote despite the fact that they had already done so a week before. Admittedly, they need the practice. Still, Rudy Giuliani had to feel a pinch of regret that his late-breaking support turned out to be really late breaking.
Of course, it doesn't help if the candidates themselves can't properly inform their constituents about when to vote. Via DCist, we have this ad from Barack Obama, which ran in Maryland, urging voters there to vote on February 5. Sorry: no, you can't.