Just my two cents, I notice the issue of giving the old parts back to the customer after the service in multiple posts so far. I've worked in several shops in various areas of the world. The thing I've noticed is a Mom and Pop shop will give the old parts back. A shop that is run like a REAL business will have the parts in the bags the new ones came in, stapled to the service tag. They will show you the old parts that were replaced and then throw them in the trash, in front of you. This became standard policy due to a legal issue after a customer decided to reuse the old parts and had an incident. The insurance company settled out of court and a lesson was learn by the industry. I can't remember for sure, I think this came up as a case study in our business of diving class. The moral of the story was reduce liability when ever and where ever you can. Disclaimer: It's not to say Mom and Pop shops are not real businesses, they just seem to have more of the we're all friends here and no one would ever sue us mentality. Just personal observation after 15 years, full time in the industry.
I doubt that is a real case, more likely an urban legend created by dive shops but reguardless of wheather or not it is a real case, they CAN NOT throw the parts away without your permission reguardless of what they tell you. YOU own them, you have paid them to replace them and for the new parts. Unless the parts are part of a trade in program, they are your parts. Refusal to return them is stealing, plain and simple. To add to that, I have challenged those who claim that there have been law suits based on the sale or use of any non defective parts for any item, scuba or not, to produce case number or some way to verify the case, so far no one has come up with one. Like big foot, lots of people believe in them but no one has ever produced one, dead or alive.