The box sets are locked up at the stores here, too, but at least they're here!
I don't xerox the coupons, I just print additional copies from the original. How would they ever know if you've already used one at that location or any other?
My feeling is that they know what EXACTLY is going on- they've got you in the store, you're going to spend money (probably more than you intended). Any loss from additional use of the coupons should be negligible.
As I said before, if these coupons didn't exist I probably wouldn't shop there at all.