The ONLY Nexus S that is truly unmodified by the carriers is the T-Mobile version, proof of this is unrestricted tethering and no carrier crap running on the phone. All other Nexus S phones have to wait until the CARRIERS modify the image to lock down tethering and add crapware, no this is not the way NEXUS was supposed to be but I suspect it was the only way carriers would agree to allow the NEXUS on their networks.
further proof of this is TMO NEXUS S's started receiving ICS 1-2 DAYS after the GALAXY NEXUS was finally launched by Verizon, same exact thing happened with the NEXUS ONE. GOOGLE doesn't have to wait for carrier crap and is able to push the update immediately......
don't be mad at GOOGLE, be pissed at your carrier, True NEXUS devices have always been on TMO, maybe consider switching, their network will be getting $5 BILLION better thanks to the failure of the AT&T merger.