Tenants leave windows open all day while gone

[Jacob Gerber]

Hello Bigger Pockets!

I have some new younger tenants who have been leaving their windows wide open while they are gone at work all day. They have even done this on a rainy day where it was predicted to rain all day (no thunderstorms, just steady rain). I happened to be over in there in the morning to look into a broken stove and  so I just closed them up most of the way while I was there. I am not 100% sure if it would have become an issue that particular day, but the rain did become significantly heavier that afternoon and with just a little unexpected wind, I could see it having become a real problem. 

 Personally I would never do this at my house. Even if the weather report said it was going to be clear all day, I have experienced enough unexpected thunderstorms that I wouldn't leave my windows open all the way.  If I wanted fresh air in the apartment, I would, however, leave them cracked a few inches at the top and bottom, but I would never leave them all the way open while I am gone for hours at a time.

For reference, this apartment is a 2nd floor apartment and on these particular windows there is little overhanging structure to help keep the rain out. There are screens on the windows and hardwood floors below them and the apartment is in Minnesota were we do get random unexpected thunderstorms from time to time. 

I spoke to a friend of mine who is another small time landlord and he thinks I am paranoid. I don't want to micromanage my tenants, but I could see an unexpected thunderstorm easily causing significant damage. So I am curious what the bigger pockets community thinks? Am I paranoid? Would sending a polite email to the tenants be overbearing? Do any of you include language specific to this sort of circumstance in your lease (I could have sworn I read a lease once that hand language about windows being left open in it)?

Looking forward to hearing your opinions.