memegui said:
Are you going to tag every post with hiiragi_tsukasa and hiiragi_kagami with sisters and every post with alphonse_elric and edward_elric with brothers?
Of course not, for the same reason I don't tag every Tsukasa/Kagami post as twins: usually it's not relevant to the picture if all they're doing is standing around being twin sisters. It's no different than with a lot of other tags: just because a tag may be descriptive doesn't mean it's always relevant. However, in some cases it is relevant that they're twin sisters so the post should be tagged as such.
jxh2154 said:
Well, if we did keep sisters and brothers then they would implicate siblings.
They already do, hence the reason for the twins -> siblings implication.
jxh2154 said:
They are not descriptive of the image and the ONLY purpose they can serve is to spoil people when it's plot relevant.
The F/SN posts are just a bad example. It's true, those posts shouldn't be tagged as sisters as the characters in question look nothing alike and the only way you would know they are sisters is if you're familiar with the copyright. That doesn't mean we should do away with the tags entirely because of that one example. The tags are useful when the characters look visibly related and and it's otherwise relevant to the picture that they are related. Most of the F/SN posts fail both tests. post #336375 is a post where sisters is descriptive and relevant.
At the very least the tags allow you to differentiate sister/sister twins and brother/sister twins, which I think is worthwhile.