Kamiza Ikioi writes "Google just sent me an email stating: 'As of May 10, any organization that signs up for a new account will be required to use the paid Google Apps for Business product in order to create more than 10 users. We honor our commitment to all existing customers and will allow you to add more than 10 users to your account for mydomain.com at no additional charge, based on the limit in place when you joined us.'" Link to Original Source
If it happens once, it's a bug. If it happens twice, it's a feature.
If it happens more than twice, it's a design philosophy.