I can back up what this article says about mobile home plumbing. I worked for a plumber during breaks from college. During the winter breaks when I was helping him, we would be rushing around repairing frozen pipes that had burst. When we would get a blast of cold air and temperatures dropped really low, we would be repairing pipes for weeks.
That was a bad situation for some of these people because, as this article mentions, they had to cut off all the water in the house until we got to them and repaired the pipes. A couple people would ask the guy I worked for about adding more cut off points to the plumbing so they could have some water when a pipe burst.
He always told them that because of the type of plumbing they had, adding more cut off points was not a good idea. I don't know whether that was because he didn't want to do the job or because the plumbing wasn't right, but he never added cut off points to mobile home plumbing.