Thanks for the replies-
I (finally) got through to someone at SWA. She said you can do that, it's not a pressure issue at at all (which was my main concern) BUT she said there is the baggage handler issue, and it can get handled pretty roughly. She also said when it goes through, if TSA thinks it's not packed properly, they can yank it.
Oh well (we never bring checked luggage, so we figured if we did check just the beverages, we would save money on the other end when we arrive- we aren't renting a car, so we can't stop anywhere on the way like a grocery store).