I don't think the case you describe is a translation to begin with.
When translating a work of art for a different speaking country than the author's, yes, we would have an attempt of translation, good or bad.
Here, in the case of a commercial product, the choice of the foreign version's title has almost nothing to do with the purpose of being faithful to the original title, author's expressed ideas, feelings or story. We have a company trying to communicate for the same product on another public. Would they have foreseen (insightfully or mistakingly, that's not important here) that the French public had more chance to come and see this movie with the title Mon oncle Philémon et ses dix-sept lapins nucléaires, they would have happily gone with it. I just don't know where to begin for examples, there are too many. We could almost assume laziness on the faithful or literal translaters' part.
So, to conclude this almost-non-answering answer, if your question is “Is gueule de bois the best translation for the English expression very bad trip?”, I would answer no. If you're discussing whether this movie's marketers' choice was good or bad, the question is clearly out of bounds here... Your asking Why is that so? questions in fact the marketers' strategy, not the French language's rules, if I may.