StackOverflow recently introduced "just in time" tag warnings. These warnings are meant to provide users with just-in-time information to help them avoid common mistakes in the tag they're using (e.g. SQL questions should mention the engine they use).
Here's what they look like:
I think CV could benefit from these tag warnings, and I'll self-answer with a proposal for an r tag warning.
Do y'all have other tags and warning proposals? Warnings can include links and basic HTML formatting. Please post below and upvote/downvote.