WTF Moment - Come on In

This past weekend provided the setting for a WTF moment with my sister in law as the star.  I have to give a little background to set this up.  When all the drama happened with the nephew back in July, this particular in-law ended up with a copy of my house key (I really need to change the damn locks again).  Now, with that being said, let's begin.  Saturday I had to travel out of town with my wife and kids.  While we were away from home, sister in law calls.  The wife explains we are not at the house.  The wife provides the sister in law with the code to the alarm system and she is able to gain access.  On Sunday, the wife and kids decided to attend church.  I was at the house (truck parked in plain view in the driveway).  Sister in law pulls in next to my truck and calls to see if I am at home.  WTF?! Why are you calling to see if I am at home?  Don't you see my truck in the yard.  Plus, didn't you just waltz into my house on Saturday?  I could not make any sense of her phone call.