Jim Barr, the Constitution Party nominee for Allegheny County (Pennsylvania) Council, was removed from the November 2013 ballot after his Republican opponent challenged his petition. Barr submitted 289 signatures and the legal requirement was 250. According to this story, the judge who removed him said that everyone knows candidates should submit twice as many signatures as the legal requirement.
Most of the invalid signatures were deemed illegible. As the story says, if the candidate can find some of the signers and have them sign affidavits, he could still get back on the ballot.