I Had both things happen to me! I thought I was just losing my mind!
The first was just like above story. I got home, It stormed overnight, came out next day to find my windows cracked ( well below door seal). I thought my dad had been driving my car and forgot, Because I would never forget to roll them up, esp with brand new Z! After I found out noone drove it, I just assumed I had to have somehow forgot.
Second situation was just a few days ago, got to apt, went in for about an hour or 2 then came out to leave and both windows were all the way down! WTF!? I never drive with both windows all the way down, always atleast up a bit. At this point I think I am losing my mind, finally I just say F trying to understand or rationalize it. I had no idea they would roll down via the fob, this could completely explain my situation.