ok, I know that I cannot take water bottles in my carry-on. But can you pack water bottles in a suitcase and check them? MIL wants to bring a spare suitcase for souvenirs---she and SIL love to shop. MIL usuallky has a car to take back all of her purchases and is concerned about transporting all of her potential goodies home. So, if there is to be an extra suitcase going down, can she fill it with water bottles and snacks and stuff for when we are down there? THanks in advance. We leave Sunday.