If you're a Democrat, you usually think "why limit it to only TWO?"
This is far more common than ever is admitted, and is very seldom prosecuted OR reported. ACORN personnel make a living conjuring up voters (even levitating the DEAD, cartoon characters, etc.)
They did it in Ohio in 2004, and they will do it in 2008.
I had the pleasure off throwing one of them off my property just prior to the '04 election.
He called me a "white racist cracker." I laughed so hard I nearly fell over.