Who Me Too'd this solution

It is not the ONT that detects the router, but the Gateway Router behind the OLT that contacts the VZ router through TR-069. VZ TR-069 is certificate based. If it does not see the VZ signed certificate or there's no TR-069 open port at all, GWR will determine you are not using a VZ router.

What are GWR and OLT? These are entirely different discussions. I don't want to throw a horse load of information at you.