This sticker was observed Oct. 21 stuck to the parking lot surface at the K-Mart in Minneapolis — clear evidence that ACORN has been illegally registering inner-city blacktop to vote. The round, red design plays off similar stickers saying “I Voted” that poll workers distribute on Election Day. But that custom may soon enough go the way of the dodo. Experts expect one third of the nation’s voters to cast their ballots before Election Day this year, up from 20 percent in 2004 — and none of those who take advantage of the various early-voting methods that are allowed in 23 states (not Minnesota) will have to go without the traditional “I Voted” stickers. So while “I Will Vote” is a nice sentiment for new registrants (wherever the stickers end up), manufacturers may find an even better growth sector in stickers with a new message: “I Already Voted.”