preventing users from creating databases

How does one prevent a user from creating a database? How can we keep users from creating databases in root dbspace? Informix tech supports says there is no way, advised to just remove them when you see them. I am a little but stunned at that reply. And I don't think this is an strange request, so I am would be suprised if no one had ever raised this question before. Any insight would be appreciated. Bill Dillinger wjd@sky.net