To hide a morph (targetGeom) channel by editing a cr2 you have to put the "hidden 1" statement AFTER the closing brace for the deltas. Whilst Little_Dragons solution works for other types of channel, morph channels are a special case.

                                d 942 0.000329997 0 -9.90033e-005 
                                d 943 1.20029e-005 0 -2.99886e-006 
                                } 
                                hidden 1
                        }

You can also use a pose to hide a morph channel by specifying the relivent actor and morph. { actor box_1 { { targetGeom Morph1 { hidden 1 } } } }