THey aren't doing it right on the sales floor. They do it in the back in a proper clean room with electrostatic safety conditions etc.
Really? Really? Have you ever been in the back room of mall retail stores? I have. It's unlikely that there will be guys in head-to-toe dust-suppression suits working in vacuum-sealed white rooms handling used & broken Apple equipment with the max of TLC. We'll be lucky if the same guy that takes in the device out front puts on gloves in the back room as he tries to make the repair himself. Hopefully, he won't sneak a cig while he's back there working on your repair.
Back rooms in shopping malls are rooms with old pizza boxes, piles of "I'll get to that mess tomorrow", changes of clothes, cobwebs, exposed AC duct work, exposed construction elements (steel beams, wiring, etc), maybe a mouse or rat or three and so on. Dust, dirt, grease, etc can all be back there because those tend to be the areas where the public can never go. In the haste of doing more business and getting to the next impatient customer, the back rooms accumulate temporary (to permanent) piles of every kind of thing. I've seen it all in Mall store back rooms.
But, if you want to believe there will be special repair labs installed in mall back rooms, you believe it. It is a more pleasant dream to imagine with this rumor than what will probably be the reality. Maybe the rats can help with the repairs?
My expectations: it will be the same people as those out front doing the repairs. Some segment of the crew will be trained for simpler repairs (they'll do themselves) and other members of the crew will be trained for the deeper repairs (they'll do themselves too). I've seen some of this within Apple Stores for years now. I question whether even gloves were used to open some of my own hardware. If you pay attention to threads, you've likely seen references to taking things into Apple stores for repairs and getting it back with dust or fingerprints under the glass (and similar). I suspect there will just be more of that now (always countered by the Apple-can-do-no-wrong crowd telling such consumers they should just be happy that they are getting some special Apple-injected dust and/or they're viewing it wrong, etc).
Someone has likely crunched the numbers and determined that this method makes Apple more more money than the old way. For those situations where this method results in having to replace a whole Apple product, the projections show that there will be X number of other in-store repairs that will be acceptable for Apple customers... so the net result is more savings for Apple... and/or probably more revenue overall from the Apple service line business. It's probably just a classic move to turn a negative (cost) line into a positive (profit) line on the ledger. If customers are net happier with the new Apple care, great. If they are neutral or a little less happy, no big deal- we just added a billion+ dollars to our coffers.