I've actually used this technique a few times with interesting results. I actually mixed my salt with a little bit of cornstarch powder before putting them into the freezer till they firmed up and were bone dry. The key to great crust is an absolutely dry outside of the steak. The corstarch with the dehumdifying aspect of the freezer achieved it. Got my grill as hot as I possibly could, weber performer with lump charcoal, and actually fanned the coals also. It started melting the high temp grommets holding the lid holder on.
Threw a couple thick ribeyes on the grate, and did indeed get an amazing sear/crust. To me it seemed to be a bit of work and I am not sure it was worth the extra effort, but the crust definitly was amazing.