Which is why I stay away from the tire monkey shops, been there done that
I went to a sears tire center many years ago with my Honda Prelude to get 2 new tires, I asked them to put the current fronts with decent tread on the rear and put the new tread on the front. Of course they threw away the tires that were decent and left me with 2 bald tires and 2 brand new tires. Had to wait another 30 minutes while they corrected the mistake.
I have a great tire guy now, he charges less than the monkeys and does a much more professional job. Plus he doesn't care if you hang out in the shop and watch.