John I'd just suggest that those people would get further if they filed a claim under the MMWA. And even then, they're not going to be able to collect on every claim.
But HD (and the individual dealers) like Ford or any other manufacturer would be a lot less quick to deny warranty issues if they thought they might have to go to court on it.
Again, out here in Calif. (thousands of riders) I've never heard of a warranty claim being denied due to a PC or an HDRT.
The 103" motor in our bikes is warrantied from the factory but if you modify your 88" with the 103" parts it "may" void the warranty. I'd say to that, that if I built an 88" motor into a 103" and HD denied me warranty work because of it, then we'd be in court. Regardless of what their paperwork says, the MMWA is not negotiable.
In other words, those parts are under warranty if we do the work......if we put it together and in the bike, but not if some other qualified mechanic does.
It may be an issue that I'm willing to push the envelope just a little further than the next guy is however, it has never been an issue for me. And I have been in a few of those little country town dealerships in places like Missouri, Ariz, Montanna, etc. and it's just never been an issue due to the high flow air cleaner, Power Commander or Thunderheader.
Our dealership Service Manager says to me "how is another dealership going to prove that the failure was due to the PC or the HDRT?" Exactly my thoughts. So the question one would have to ask theirself is "am I going to lay down for this.....or am I willing to put the time and energy into fighting for my rights?"