At the moment the tag aliens is ambiguous, as the tag wiki states itself:
Generally, indicates the presence of extra-terrestrial beings in a film or television project. Can also specifically refer to the second of the Alien movie series.
I think one tag should not refer to two completely different things, because that way it becomes completely useless as a filter.
In this scenario, it might still work if I am interested in questions about aliens in general, because the second Alien movie happens to fall into that category. If I however want to specifically find questions about the movie Aliens by James Cameron, I have to dig through all the noise of movies having aliens in them.