I just purchased a Traverse LT1 three days ago which didn't have the tow package installed by GM. I was assured that it would increase the tow capacity from 2,000 to 5,200 at the time of sale. After seeing this and related forums, I called GM directly and they really couldn't give me any answer other than 'if the V92 package isn't installed it can only tow 2,000 lbs'.
After showing this discussion and related forum discussions, they contacted GM themselves and acknowledged that there is quite a bit of confusion about the different tow ratings. I'm still not 100% convinced that it won't screw up the tansmission, so to cover myself (at least during the warranty period) the dealer agreed to also throw in the transcooler as part of the installation and gave me a WRITTEN guarantee that it would now be able to tow 5,200 lbs and NOT VOID the warranty.
The only thing that they couldn't do was install the tow haul switch, but by using the manumatic shifting, I would be able to minimize excessive shifting - in addition to having to turn off the backup sensor.
My advice, make sure you get something in writing to cover yourself in the event that you need to tow anything above 2,000 lbs.