I personally would opt for adding the tag if you think it's applicable. I rarely get complaints from readers about stories having a few extra tags, unless they were looking for something specific, like seeing a tag for WS and not finding any WS content. On the other hand, I do get a lot of feedback from readers who feel a tag was missing, and who were unpleasantly surprised as a result.
One of the biggest things I do look for as a moderator is what we call "trigger" tags, for content like Rape, Incest, or Minor1/Minor2 just as a few examples. These denote content that can have a very strong effect on readers, and that needs to be disclosed, even if an author might think such tags constitute spoilers. Again, for myself, I tag even if the content happens offscreen, or is only lightly touched on in my story. The last thing I want is to cause someone emotional harm.
And you can always PM me or post in the General Staff Questions if you want to ask about something specific. I'm happy to help!