I absolutly agree with all the above but I had an interesting conversation with costco a little while ago when getting a new tyre fitted on my parents car. The car needed front driver side replaced so went to the counter and sorted everything out, bit of paperwork to sign and the chap said they would have to swap the rear drivers to the front so that the newest most grippy tyre was on the rear for safety!? I challenged him as it didnt make much sence to me and he said it was policy and its more important that the rears have the best grip regardless of being fwd, rwd or awd. He would not fit the new tyre unless they swapped round!? Anyhow as soon as I got the car home I swapped it so that ths newest tyre is on the front.
Iv not really explored this, I dont think the chap was being an arse but costco seem to think its the right thing to do. Any ideas to the logic cause I cant think of any