Yeah I have encountered many a cut harness, its always off to Best Buy or Walmart. I learned at 16 to do my own installs, and it absolutely amazes me the stuff that people do to their, or other peoples cars.
When my fiancee and I first got together, she had/still has a 92' Camry. The rear factory speakers were shot so I decided to install a set of 3 way pionner 6x9's I had.
The install for those entails removing the back seats, and rear dash because they are drop in. A (dumb) friend stopped by, had been drinking a bit and decided he wanted to help on the install.
Next thing I know he has his pocket knife out, and was trying to pry up the stock speak grills in the rear dash.
I'm like WTF?!? and he argues that it would be easier to get to the speakers by removing the the factory grill by prying it up with a pocket knife.
He was promptly asked to leave.
And I finished my install.