I'm not sure that it's an actual NCNS that I would be concerned about, but rather being charged back with one even though it's not true. How do you prove, for example, if you have no signal on your cell, or they don't have a working phone #, you go to the house, even leave a door tag, and the customer denies it, hoping to get a discount, or just not wanting to take the blame themselves. It has happened to me in cable TV many, many times. How do you prove you went to a customers house, if they claim that you didn't. Take a picture? The HSP could just claim you took it after the fact. You know as a contractor you are always guilty until proved innocent beyond all possible doubt. At least that's how I've always seen it, unless you work for an outfit where their is some mutual trust.
When I see those kind of high charge back rates in a contract, I tend to stay away, because it gives me the impression that the company writing the contract has a strong interest in recouping some of their subcontract costs.
That is just how I look at it based on over 20 years in this business.
