[randartie]

What's stopping ISPs from slowing down other speedtests at the same rate as netflix to eliminate your ability to have a 'control'?

[dpcx]

You can have any "control" you want by setting up your own "speedtest" mirror. It's hard to stop all of them.

[scott_karana]

Wouldn't your results show as being dramatically lower than your purchased speeds, then? That would backfire in a hurry :)