Cruising from Galveston in 2014? If you bring booze or cigarettes back, be prepared to pay a state tax - $3.50 per fifth of liquor for example. The state TABC will have officers with their own checkpoints as you leave the terminal.
I imagine if you say you have nothing and they pull you aside for a baggage search and find you are lying, it won't be good.
Read more here
They plan to expand the operation to the Houston cruise port at some point.