The idea of pantyhose under shorts is actually useful for free members wanting to search the simple combo of pantyhose and shorts worn by a single character since a pantyhose + shorts search will include every post containing more than 1 character where at least 1 of them is wearing shorts and at least 1 is wearing pantyhose
This issue is almost always present when searching for more than one tag without adding solo to the search. It's not an issue with any individual tag's existence or potential removal, it's a critique of the way the tag system works in general - just because post #6130616 shows up in a holding_sword holding_gun dual_wielding search, doesn't mean any of those tags are bad.
As for the tags in question, I think they're garbage tandem tags that are completely obsolete with a simple shorts pantyhose or shorts leggings search. Both of these searches will find all properly tagged legwear_under_shorts posts, while also providing the benefit of catching the large number of posts that have been tagged with shorts, pantyhose and leggings, but not legwear_under_shorts. However, given the negative reception lately to nuking even pointless tandem tags, I don't see this BUR as likely to pass.
However, even if we decide to keep legwear_under_shorts, pantyhose_under_shorts should at the very least be aliased to it. The wiki's been deleted for two years and even already directs users to use legwear_under_shorts instead, so at this point it's just a formality. I'll propose a BUR for that as a counter to the original BUR.