See my response, on this same issue, to ‘Sherri Butler’ below.
There have been many problems regarding poly piping systems in houses which have been widely reported and for which there were (are?) many concerns. Some concerns are legitimate and others may not be. Most home inspections will point out the presence of poly piping and some will call for further evaluation by a qualified and licensed plumbing contractor.
If there have been leaks in the system before, then the cause for concern rises.
The cost to re-plumb a house is significant and a home inspection is not intended to determine whether you do or do not have an actual problem with the installed system, only to bring to everyone’s attention that this system is present and the problems were so great that there have been class action law suits regarding these systems.