On this question's revisions you can see that the tags were changed twice. The first time "system-recommendation" was added even though the question didn't ask about a system, and stated the system in another tag. The second time that was removed and campaign-setting was also removed and adventure added.
I think campaign-setting was appropriate for this question because, considering it came from the original poster, it implies that they was willing to pick the campaign's setting based on what material they could find.
Further, neither adventure nor campaign-setting have any description about what they are to distinguish them apart. I like when people edit a post to add something obvious (Like the poster says they're playing in D&D 3.5e but forgets to tag it) but this seems to be simple opinion of how someone else would tag it turning into something enforced.
Is retagging in this way something that is encouraged on the RPG Stack Exchange?