To provide an extreme example; if you have sex with someone without asking them, it's rape. "But baby, I assumed you wanted it because you had a glass of wine

To provide an extreme example; if you have sex with someone without asking them, it's rape. "But baby, I assumed you wanted it because you had a glass of wine and you were wearing that sexy outfit." - Still rape. Opt-out telemetry is like that, too, you stop only after penetration. Or another example, if architects decided to start putting cameras in the house everywhere. The camera, somehow, blocks out your face but monitors everything else. "But, we need this data to figure out which part of the house you're using and how often you're in these rooms. PINKY promise it's anonymous and no one will know who you are." Opt-in consent is the only right way.