This isn't good advice. The locally owned ones are often even more desperate and willing to go the extra mile to defraud you. The idea that small businesses are more honest than big ones is a complete myth. Most of the time it is the reverse: big corporations have more to lose.
The advice to go local is less about it being a guaranteed win and more about it being how you find those who will go above and beyond everything.
I've actually never heard anyone say "The advice to go local is less about it being a guaranteed win and more about it being how you find those who will go above and beyond everything."
Instead I always hear a dogmatic something like "support local business! Big corporations are evil!" When I've actually been defrauded out of FAR FAR FAR FAR more money by buying local.