You are so incredibly wrong here.
Try calling up a shop and telling them to stop selling their equipment and just make money off installs and see how long they last. I won't even get into all the shops I've witnessed going out of business after accidentally (or not..who knows) installing stolen equipment, word getting out they were doing so and/or their rep trashed, and people basically cutting them off completely. Liability the same? nope. Labor=pure profit....nope again as even with labor there are costs involved that detract from making "pure profit". My logic flawed?

/hijack

/thread

 

in my shop we will notify the customer that although we do warranty our
labor for the life of the car it is only what we install. So if a radio blows because if wiring we did not install then it is not our problem. Most of the time if they had not previously had anything installed they need our parts to get the garuntee. Our wiring may be expensive but we back it up. And the wires are really profitable considering the mark up.