It is already implemented, otherwise they wouldn't be able to enable it once the subscription is active.

Why should the OP need to pay a subscription to enable a feature that is build into the camera, that is a standard feature on other cameras and imposes no ongoing costs to the manufacturer¹? This is an example of gouging, pure and simple.

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[1] unless they are forcing the user to use their hosted service for steaming the webcam output, in which case there is some bandwidth and perhaps other processing cost, but that is on them for having not just implemented a standard that enables local-only recording