This seems like a bad idea to me. Making a tag to be used for entirely off-topic questions will just enable people to ask those questions easier.
Recommendation requests are typically closed very quickly anyway. If they have a net negative vote record and no answers, they'll be deleted automatically anyway after 30 days. That's short enough that it doesn't really dilute the count of bad questions in any given tag significantly. Users with enough reputation for the moderator tools privilege (currently 2k) can accelerate this by casting their own delete votes on the question 48 hours after it's posted, which will also deal with the rare case that it has answers. If the post reaches -3, trusted users (currently 4k) can bypass the 48 hour restriction and vote to delete immediately (and moderators can always delete), but this kind of deletion isn't particularly urgent in my view.
If the question sits at a net score of 0, it will be deleted after a year, and if it has a positive score the automatic deletion script will never delete it. In a case like this, when the question is clearly and completely off-topic and the OP didn't read the rules, downvotes are merited, so these questions should always get deleted.
Deleting these questions should be our ultimate goal. Making a new tag to move them to only to have them be deleted soon after seems like a lot of work (it will need to be recreated frequently or we'll need to use a hackish workaround like what we did with retag) and I'm not sure I see a lot of benefit.