I have noticed that the Williams F1 Racing Team have shed the Martini branding this last race (and maybe the race before as well; I don't recall). It's nowhere to be found on the car, the racing overalls, even the name of the team has changed (although the official championship entry is registed to "Williams Martini Racing"). Most obvious is the omission of the red lines on the car's typical Martini livery.
Has this to do with the specific venue, Abu Dhabi, where maybe alcoholic sponsoring is forbidden ?