Curious incident..Part 2

On a rather beautiful Saturday morning, my second sis and i were lazing among the bolsters and pillows on our parents' bed. The TV in our living room suddenly blasted out loud.

"First sis, heeeyyyy, tuurrrnnn dooowwnn the volume, wiiilllll ya!!," yelled my second sis. A minute later, my first sis came into our parents' room and went: "Hey, who switched on the TV! You're not watching it, so why switch it on?"

There were only three of us at home.