Is there an "official policy" for the oversized plastic bags that Alaska provides customers for car seats and sports equipment?

On occasion I want to wrap my checked duffel to protect it from moisture when flying to a damp area such as Seattle or Portland. Sometimes other people's luggage can leak too.

I was read "the riot act" when I politely asked for a bag today and was told that "she knows the official policy since she has been with Alaska for 22 years and they are not to provide those bags other than for car seats or long sports equipment." She unprompted, gave me her name and told me to feel free to check out the policy.

If that is the policy I totally understand but it has never been enforced in the past. Sheesh!

She was super helpful and suggested that I can go buy a trash bag. They work great she said.