That way, A child may have a limit on 10 messaging interactions a day. Posting a message on the forum or comment/etc may deduct one usage. Or they can only submit messages outside school hours.
So the plugin needs to call CHECK with NO logging to approve the message, on failure tell the user why (out of message quota, not allowed at this time etc) or if allowed, post the message and call CHECK again WITH logging to record it.
In the end, if the check succeeds, the post goes ahead. If the logging fails, it's sort of irrelevant.