Is it ok to hit driver from in front of the mat?

No.
The wear from standing and hitting alone is enough to cause bare turf when the growth is slow in the spring and fall.  This photo demonstrates that the theory that a player will only hit drivers is false.  We are trying to provide a quality facility that members are proud to show guests, please respect the "mat only" restriction on the range.  

Once temperatures reach what is needed for bentgrass germination, there will be a recuperative potential for the range turf.  At that point, we will open the range on the grass.

There is a small trick to getting a tee into the mat, but once mastered, the rewards are great.
Line of thunderstorms coming, we opened all three nines for the weekend.  Carts are paths only, we are still pretty wet.
I'm out of the masters pool, might as well go fishing.
Turf

-- Sent from my Palm Pre