I think the "corners" that are being referred to as being cut are ....not
having the rotors turned, spec'd to make sure they are still within
tolerance, putting things like anti-rattle clips back on,( may not pertain
to your application) not using the "goo" that comes with some pads(that
nasty stuff that is "supposed" to keep the brakes from squeeling, it dries
to make a rubber/silicone cushion), not checking your calipers,(torn boots,
piston sticking,seals etc.) , not making sure that your rear brake hardware
(springs etc.) are in good condition, again spec'ing the drums to make sure
they are still servicable, after turning, and one last thing right off the
top of my head would be surfacing the rotor surfaces after they have been
turned. Most shops around here don't do that unless you ask or are fortunate
enough to "watch them" while they are doing the job. We usually just use a
small "die grinder" with a fine grit wheel and go around the rotor to take
the "edges" off the lines left by the lathe. ( before the flaming
commences..our lathe doesn't leave these huge lines that you may be
imagining in your mind!! Just the standard finish, ok now you may flame me
if you like!  :~)  ) Tom