If we were to change the tag from "legal" to "regulations", I think there should at least be a re-direct, as most people asking (on-topic!) questions about legality will try to tag their question with a "legal" tag, if they haven't been here for long enough to know about a "regulations" tag. Constantly we will have people trying to re-create the "legal" tag if there is not at least a re-direct.
Also, as an alternative to completely removing the tag, we could make the first sentence of the description of the tag, be very clear that not all legal questions are on topic and more information can be found in the FAQ (or wherever the information ends up being). This may also prevent people from asking "off-topic" legal questions. Simply removing the tag will not have this latter effect.