A bit too late, but there goes nothing:
We do not need legal. Its description says:
Refers to any question related to the application of laws in aviation
Which is what regulations are for, since regulations (e.g. 14 CFR) have the force of law (e.g. US Code). (The two examples in @Pondlife's answer already have tags for regulations.)
Note: a generic regulations tag exists and is used 207 times.
There are 12 questions that are tagged with [legal] but not [faa/regulations]. After perusing them, 3 of them are IMO off-topic, and 9 are mislabeled (wrong tag usage).
Due to the vagueness of the description, it leads to questions being asked and closed.
IMO Law.SE is the best place for a question that needs statutes and/or past court cases, i.e. the il/legality of a topic.