I have no problem plugging a ball regardless of where it comes from. What erks me is, I use to have a customer who would come in and say "is this a good ball for me, and how would you drill it to do this , in this house?" So I spend 15 -30 minutes explaining the why or why nots, two days later he comes in with the same ball drilled the same way we had talked about from another pro shop. This has happened 3 times with this same person, now when he comes in ( knowing he's wanting info ) I ignore his requests. By the same token he'll drive 100 miles round trip to save $15 bucks on a ball, but he'll ask me to do his resurfacing on all his equipment to save a trip of 100 miles and to save $4.00 per ball, go figure!!
On the other hand I have a husband and wife that in the last calendar year have spent $1526.00 on new balls, shoes, and plugging their older balls for their son. They buy a new ball on average every 60-90 days, and that is not counting any other accessories. They get an additional 10% off on anything they buy due to the amount of money they spend, the next guy comes in he buys the same ball and pays $24.00 more on the same ball, (he buys a ball once every 3-4 years whether he needs one or not, lol) and asks why? Is this an unfair practice? I don't think so, take care of your customers and they will take care of you.