At the Walmart in Yuba City, they gathered Thanksgiving night around goods wrapped in black plastic in aisles marked by yellow caution tape. Maps listed shopping events that began at 8 p.m. when customers could buy discounted hand mixers, vacuums, computer equipment and video games — “Zombie Hunter” among them. Two miles away at the Target on Butte House Road, shoppers waited in a line that reached around the corner of the store for the 9 p.m. opening. At the start of the day, hundreds were in line for the doors to open at the Kmart on Gray Avenue — …