Here unfortunately the trend is that the artwork person is supposed to be a magician. Give the design late and expect the artwork to be produced immediately. So a good vendor stops caring about the quality and bad ones mushroom, because they can deliver faster. And you end up appearing obstinate, obsessive if you insist on these issues. My current vendor had a customer telling him that ground planes create problem in a uC design. Now atleast in my designs he follows the rules, but after 3 years of browbeating and bullying.