Question : Standard User Able to Add Computer to Domain

It has recently come to our attention that a standard user is able to add a computer to our domain.  For example, one of the members of our QA group can create a new VM and add it to the domain using his credentials...which are those of a standard(non domain admin) user.  Is this normal behavior?  If so, how can we prevent it?  If this isn't normal, any suggestions on where to look?  Within the "Advanced Features" view, I have already looked at the  Security/Effective Permissions for this user and he doesn't have rights besides Read.  As a test, I have attempted to add a new VM to the domain using a test user without admin rights and that works as well...so this isn't specific to any one user.

Answer : Standard User Able to Add Computer to Domain

Yes, that's normal; by default, a user may add up to 10 workstations to the domain. Set the ms-DS-MachineAccountQuota attribute described in the following link to 0 to prevent this from happening:
Default limit to number of workstations a user can join to the domain
http://support.microsoft.com/kb/243327