[SeaDweller]

A head on collision at 12mph would cause an immediate deceleration, which would more than likely cause the bags to deploy. In your case, a "T-bone," there was continued forward movement of the vehicle, along with an "activation" of the crumple zones. I may be wrong, but it seems the system worked as intended.

Folks have received worse injuries from air bags, then they might have from the accident itself. Had the air bags deployed, you may have been looking at the prospect of neck injuries, a broken nose, etc. Instead, you walked away unharmed.