I would refuse the bags, not pay for my purchases and leave them at the bottom of the checkout chute.
Repeat until the law is repealed.
Gibsmedat free bag.
Exactly the way to fight the law. Make it cost something to the market to continue this stupidity, and suddenly they'll find some interest in getting this law repealed. Exactly my plan for when this law goes into effect in all of California. I've already had Target and other stores in the People's Republic Of Pasadena bag it rather than refund the purchase. One tried to sneak a bag fee onto my bill, and I told them they can refund the entire purchase, or they can refund the bag fee - they refunded the bag fee.