I think this is how the NSA became the NSA as we know it today. When your task is to prevent terrorism you need to see. You need to see in time and detect patterns. So you need to store as much data as possible because.
So it's good to stick to some boundaries. In the example of the robot: you could measure room temperature, because maybe the sensors are acting to it. Or you could measure the amount of people in the room because sensors could act to it. Heck, maybe the sensors are acting different to different people, so track there faces and store it. Well maybe sensors are sensitive to somebodies smell so track that too.
So it's good to stick to some boundaries. In the example of the robot: you could measure room temperature, because maybe the sensors are acting to it. Or you could measure the amount of people in the room because sensors could act to it. Heck, maybe the sensors are acting different to different people, so track there faces and store it. Well maybe sensors are sensitive to somebodies smell so track that too.
There are limits to what is useful to track.