I did it because I didn't stick with my norm. I only lock the door by using the key fob in my hand. That pretty much guarantees I won't lock them in. But I thought the keys were in the house, didn't want to walk back inside, so I hit the door button and closed it, only to find out 10 minutes later .....
And I also discovered a software change. I did this once before in my 2000 GMC while on travel. Again, the window was cracked so I was able to sneak a rod thru and hit the door unlock. Didn't work this time. GM must have gotten smarter; on my 2014 you can LOCK the door by using a rod to push the door button, but the UNLOCK and window up/down are disabled if there is no one sitting in the seat.