So, I’m looking for others to verify this if possible (video above).
All you should really have to do is tether your cell phone to your PC. Make sure that it is the internet connection you are currently using. Stream a video from YouTube while signed into your Google account. Then sign out of your Google account, stream the same YouTube video and compare.
If you are effected you will have a very similar result to what is shown in the video above. One note here is Google seems to be very closely matching it’s throttling to the traffic history of your mobile ISP. So typically throttling occurs during peak hours say 1:00pm to 12:00am. I always use 360p 30fps for the best indications but try’em all. 
Good hunting. 