What Plugin Does This?

[HUMMERh3]

I have a lot of plugins on my board and for some reason my vBulletin forum is automatically pruning some members. It's only a few newly registered members. I'm trying to find out which plugin to disable. Any ideas?
This is the email it sends out below:

Dear User_xyz,

Unfortunately your registration at This Forum did not meet our membership requirements. Therefore your registration was deleted.

Sorry,
This Forum

[Lynne]

Perhaps you should print out the list of Products you have (and plugins under the vBulletin heading) so we can see what our choices are.

[vbenhancer]

any idea? what did you install to filter users?... you're supposed to be the one with the idea... think of it a little! i'm sure you will find what it causing this. if not, you have way too much pointless products in your vBulletin.