Require a Custom Taxonomy to be checked

I have a custom taxonomy, “position”, with multiple terms for a custom post type, “employee” in the admin. I want to validate the form to require a position to be selected when you save/update a post.

How do I validate and make the position custom taxonomy a required field in the wordpress admin?

Also, I’d like to display an error message to indicate to users that a position is required to be checked.

Thanks!

I’d say, hook into pre_post_update and check what is given via $_POST…