I was reading thru Xbox Enforcement Myths and found that XBLPET has changed their policy on the free of charge offending Gamertag change.
The FAQ paragraph below was taken from the following link
I received a forced Gamertag change. Can XBLPET let me choose a new Gamertag for free?
Some rumors give the impression that XBLPET will provide a free Gamertag change to accounts that have received a forced Gamertag change. This is not the case.
In the past, a forced Gamertag change gave users the opportunity to change the offending Gamertag free of charge. Unfortunately, this gesture was prone to abuse, and many people simply chose new, equally offensive Gamertags. As a result, the Gamertag enforcement process changed. A forced Gamertag change now automatically assigns a new Gamertag to the account, much in the same way a system-generated Gamertag is provided when you first sign up for Xbox Live.