The Verizon UIDH is added to the content headers
After the HTTP request was completely built within the browser/client. I would imagine that any smart (dumb) reader of your HTTP requests would simply ignore fake ones injected during legitimate surfing and pick up the one illegitimately (and probably illegally) by your ISP.
FWIW, I've submitted comments via http://amibeingtracked.com/ to Verizon Wireless and the FCC and separately to VZW during a bill payment discussion. I say For What Its Worth because the corporations can't admit that what they're doing is wrong without getting slapped with lawsuits.
I also use a proxy service (PrivateInternetAccess) which should prevent this type of behavior but might introduce its own flavor of tracking... Just sayin'.