Adding a shim inside the scope rings

[kt]

I have got an issue that is getting rediculous. bought leupold rings for my new 700 after one smith wouldnt touch them the next installed the rear base backwards so that the bolt wouldnt open. now he's fixed that but i notice there is a thin piece of metal laid in the bottom of the rear ring with the scope clamped on top of it. Is this a normal practice or a short cut of incompetency? thankyou
kt