scarlet letter
n.— «The court became the first in Ohio to immobilize the vehicles of repeat OMVI offenders. Adkins also began ordering repeat offenders to put yellow license tags on their automobiles as “scarlet letters,” he said.» —“Court of Appeal; Fun-Loving Yet Serious Circleville Judge Makes An Impression” by Jim Massie in Circleville, Ohio Columbus Dispatch (Ohio) Sept. 2, 1993. (source: Double-Tongued Dictionary)