Actually, I have looked, and I have never seen a picture or any word of George being on a cruise ship - Carnival or otherwise. At the announcement by Carnival he said "I have never even been on a cruise ship, but I am going in December" but then there are no pictures or record of him having actually gone.
I have never heard anyone say they heard on a cruise, "this comedian was selected by George Lopez" - as far as I have heard most of the comedians have been the same ones who have worked for Carnival for years.
It's not a big deal. but I just wonder why anyone would care to promote someone's name who really isn't doing anything.