This is a silly ?, but packing light is important to me.... Plus, I'm a first time cruiser and am pretty clueless. I've read that lots of people highly recommend packing a magnetic dry erase board for your cruise door so folks in your party can leave messages for you easily. Why would you need this if you have wave phones? Wouldn't it be easier to just text a message with the wave phone? We plan to have wave phones for everyone in the party. Thanks for any info!