What the hell? Sounds like something's not clicking in your kid's head. I mean I can understand letting some cool air from a window, but opening a window to let in FREEZING air and leaving the window open long enough to FREEZE your plants? Yeah they need to stop being so forgetful and be respectful/mindful of other people's stuff. If the room is getting that cold (yes I realize the plants are near the window, but still), I don't understand how they can stand to leave the window open that long unless they're running off after opening the window. I say beat it into them! They're never too old for a good old fashioned spanking with a leather belt!