The BCT15 does not have preprogrammed frequencies that can be erased. The mode that allows you to select your state uses frequencies that are hard coded directly into the scanner. The memory which is used to program systems directly into the scanner is empty from the factory so using the hold + 2 + 9 reset will only delete systems the user manually put in.
To turn off the hard coded state frequencies simply press the POL and HP keys repeatedly until the PL, DT, HP, and BT are no longer showing on the bottom of the screen.