In time for campaign season, Mayor Parker announced yesterday that the city would begin cracking down on bandit signs placed on public property by fining violators under an existing city ordinance that — as far as she knows — has never been enforced. Political candidates will be given 24 hours’ notice for each violation before being charged $200 a pop, she said. Collected funds will be used to defray the cost of removing the signs — which reached $450,000 in 2009.