So after reading the "Terms and Conditions" for the offer, it doesn't appear that they are supposed to offer free drinks on Embarkation Day from Galveston, so I'm thinking anyone that did get them on day one was just lucky?
"Drinks benefit is valid for the eligible VIFP Club Member and one travel companion (assigned to the same stateroom). Must be 21 or older to purchase and/or consume alcoholic beverages. Due to Texas state law, our Drinks On Us! benefit is not available on embarkation day for sailings departing from Galveston, TX, but will be available at the start of day two. Additional restrictions may apply. Carnival Players Club® reserves the right to change or cancel this promotion at any time."