Ok, just committed a rule-based check for that. Don't forget to recompile/copy new binaries, update the database, and set the rule to true - in that order.
(If you don't know which rule_set to use, set them all to 'true')
What you will see is the player attempt to scribe the spell, then the server kick out an error message saying that the "item is not usable..."
Being rule-based, and in the main repository, it allows many people access to this feature without having to add it as custom code.
And being defaulted to 'false,' it doesn't change the original server behavior
EDIT: For anyone wanting to use this rule, just change to race mask of the item to only those races you wish to use it. The default appears to be 65535 (all races.)
(Don't forget to re-run shared_memory)