It is only 1 of a couple of titles that carries this warning, again if you choose to use and you get banned, CH is not responsible.
On the other note, I have no idea why your trainer isn't working.
Make sure you have added the trainer to all whitelists of anti-spyware and anti-virus software you have, and also allow access to the net through your firewall.
* Updated game trainers and cheats daily
* Get notified when new cheats are added
* Request which games get new trainers
* Priority support with any problem