Sony Pictures Animation’s debut pic, “Open Season,” shot to No. 1 over the weekend, bringing in family auds to the tune of $23 million. “Open” had been projected to be in a tighter battle for first place with Disney’s “The Guardian,” which came in well behind at $17.7 million. “Guardian” has taken an unusual approach to its ad campaign, touting its exit poll results as being some of the highest numbers in studio history. PG-13 Coast Guard drama, starring Kevin Costner and Ashton Kutcher had a per-engagement average of $5,451 from 3,241 playdates. CG-animated “Season” — about a domesticated grizzly bear forced back into the wild — hunted $6,001 per playdate from 3,833 screens. Pic, the frame’s widest new rollout, was a solid performer in a year that has seen some animated fare falling flatter than usual.