Aliasing schoolgirl_uniform -> school_uniform instead of current implication. That's why it's not created through alias form.

Reason:
Gender specific version is unnecessary.
I also suggest to alias schoolgirl to school_uniform, or to invalid tag. Schoolgirl is gender specific tag that is redundant if it means uniform, and too ambiguous if it's supposed to mean real schoolgirl.
I have same issues with having maid/nurse tag alongside with maid/nurse_uniform tags but this tag is additionally gender specific, and we're avoiding this type of tags here.