If I get film back with scratches, dried in dust, or other blemishes, it seriously compromises my faith in that lab's ability to meet my standards. I understand that errors occur from time to time, but I will not accept them. My father used to send volumes of chrome to Duggal every month (on the order of 600-900 rolls) when he was photographing full time, for 15 years and I have never heard him tell any horror stories. When he switched to ColorEdge (now CRC) for color negative processing, sending the same amount of film, it was the same case.
It's a lab's job to give you professional results.
A certain quote from The Rock comes to mind.
"Your best? Losers "try their best". Winners go home and f**k the prom queen.