Setup an account with:

0) 1 Virtualization
1) 1 rhel-server entitlement
2) 1 rhn-tools entitlement
3) 1 rhel-vt entitlement
4) 1 registered RHEL5 System
5) Login and add Virtualization to the system.  This should consume your 1
rhn-tools and rhel-vt child channel subscriptions.

Verify that you are out of rhn-tools subs by going here:

https://rhn.webdev.redhat.com/rhn/channels/software/Entitlements.do

6) Then, *remove* virtualization from the system.
7) Attempt to re-add it and you get an error stating:

"You cant add virt because you are out of rhn-tools subscriptions"

Since the system is already subscribed we shouldn't try to subscribe it *again*.