The do not need an API call, obviously they know that the video is being watched, because it's being streamed.

YouTube serves videos from CDNs, many of which it does not own.

I missed the part where that's our problem.

	▲	zeroimpl 4 days ago \| parent [-]
		Metrics from the CDN will be wildly inaccurate. Also downloading a video isn’t the same as watching it.