First off, I assert that whether Verizon is actively throttling packets, or simply not providing sufficient peering to get to Netflix, they are committing fraud by advertising high speeds and not delivering them.
However, to *really* convince people, more rigorous experiment has to be performed: find a VPN (or set up your own with a colo) that's connected as closely to Verizon as possible, as close to their peering with Netflix as possible. That way the route between Verizon and your VPN/colo is as similar as possible to the Verizon<>Netflix route. You can then measure Netflix bandwidth to your VPN/colo, and the resulting full-path bandwidth.
I *strongly* suspect you'll see the exact same behavior, but by doing that you've proven beyond a shadow of a doubt that Verizon is absolutely to blame. It still doesn't separate the packet-throttling scenario from the insufficient-peering scenario, because even though your Verizon ingress point is ideally the same router, Netflix is *supposed* to peer to that router through dedicated lines (e.g. trunked 10G to the next room over where Netflix's router is).
Of course, since Netflix has offered to both purchase and install the 10G cards and wires on their own dime, that scenario is absolutely no different than packet-throttling. Except that in order to do packet throttling, Verizon had to spend *more* money on hardware than they would have to just add more capacity. Now *there's* a bit of research to do: $ to throttle vs $ to add capacity.....