On the day before Thanksgiving, protesters, seeking better pay and benefits, clog the intersection of Century and Sepulveda boulevards. A dozen are arrested after defying police orders to disperse.The day before Thanksgiving is one of the busiest days of the year for Los Angeles International Airport, and union organizers knew it would likely send a message if they could snarl traffic by marching through the streets and clogging a heavily used intersection near LAX.