I'm sorry to hear that as I too have felt your pain. At one point, I had 3 new Grips in a row come in horribly off-centered. 3 completely different models, full sized Ritter, mini Ritter, and a mini sheepsfoot (555). They came from 2 different venders, over the course of three months, and they all leaned in the same direction.
$5.80 later, in a USPS priority box, they were sent to Benchmade for repair, all at different times of course. I would receive one, see that it was off-centered, send it in to BM, repeat. I'm happy to say that they were all repaired correctly, and returned within 2 weeks. Other than being somewhat frustrated having to spend time and money shipping them back to BM, I am happy that they are right and know that BM stands firmly behind they're products.
I guess what I'm trying to say is that it happens pretty regularly, but there is a solution, albeit it require some effort on the customers part. FWIW, after getting those 3 Grips that were bad, I'm still buying BM products without hesitation.