It's logical so long as ownership of the tune is firstly agreed upon.
If you have commissioned someone to build you something, especially when charged an hourly rate I think that the client has ownership unless otherwise specifically stated.
This means that the owner has the choice whether to share their tune with someone else or not.
Who would let a workshop tune their car if they knew they, or another workshop later on couldn't view it. Either to enhance or edit the tune (because of an additional mod to the car), or to check if the orginal tune was the reason their car blew up?