You'd also have pets captured, curtains flapping by an open window captured, and any toys kids are playing with (like balls) potentially captured as another viewer too.

Meanwhile pap who likes to sit motionlessly while the kids round around him, isn't detected.

> without invading too much on people's privacy

Motion detection feels like a pretty major privacy violation to me.

> You wouldn't know the age, but you already have ton of information by knowing the address and the subscriber already.

Except when you have friends or family over.