I really think, I don't care what you tell the customer, if it fails it will be your fault for installing it.
I don't think I've ever met a customer who openly accepts the blame.
Just like when the HO hires a hack to do the work rather than a highly qualified contractor whose bid was much, much higher. They never blame themselves. They blame the hack.
Imagine if people shopped around for doctors like they do contractors. HO needs his appendix out. One doctor at a highly respected hospital wants $65,000.00 to perform the surgery. But, a guy the HO works with, knows a guy who tinkers on weekends who will do it for $300.00. It has to be cash though.