The proliferation of illegal A-frame and flag banner signs as well as illegal human signs on Manteca sidewalks could become legal by the start of 2013. But to avoid sign seizures and potential fines, businesses may have to secure permits and provide the city with proof of liability insurance. That’s the bottom line of a proposed sign ordinance amendment being mulled by the Manteca City Council when they meet Tuesday at 7 p.m. at the Civic Center, 1001 W. Center St. Should the council approve the changes, a second reading would be required at their next meeting on Dec. 4 as the second meeting in November is being cancelled due to non-paid furloughs to help keep the city’s general fund balanced.