Some orders should never happen: an accessory checking out without its base device, two products that can't ship together, or a bundle item bought again on its own. CartGate blocks these carts before checkout. Set rules by product, variant, or collection, and choose to block the cart or warn the customer on the product page. Your rules hold no matter how the customer checks out, including Apple Pay and Shop Pay, so you stop refunding orders that should never have been placed.