This has been discussed many times, in regard to many different vehicles, and what those vehicles all have in common is that it is possible to lower the vehicle’s windows remotely via the key fob. Somehow or other, pressure is being applied to that key fob while it is inside your purse or your pocket, and the result is that the windows are lowered.
Read your Owner’s Manual for details, and then change the place where you keep your keys.
Here is the most recent post from another forum member on the same topic: