Today I was really out of it. I had to go to a funeral and was rushing to get ready in time. I put Kili in her cage and dropped a bowl with food in the holder and immediately left. When I got home 7 hours later, I open the door to enter and there is Kili sitting on top of her cage getting all excited. Immediately I spotted the open cage door and I almost fell over. Meanwhile she was greeting me by saying "hello," eyes pinning, and clicking her beak. I expected to see papers torn up and keyboard destroyed. But to my surprise everything was just fine. Most of the poop was concentrated in the cage area and the other places she visited being safe and without problem. She didn't wreck the keyboard or go on my couch for that matter. From all evidence, it appears that she stayed on top of her cage the entire time and only paid a few short visits to other areas. Luckily my home is bird proofed and nothing important or dangerous is left out. It appears that she behaved no different than if I were home to supervise her when she is out.
I'm not saying I would do this again or that it's a good idea, but I am happy to see that she is pretty well behaved in general. The good news is that she was out mid day and she is used to normally just spending quiet time in her cage relaxing during this time (she's much more active in the evenings). Furthermore I had flown her in the park this morning and showered her. So she was probably tired and mellow from the exercise and moisture. I still have to be cautious not to tread in little nuggets but it looks like all ended well. Normally I'm good about closing the cage right away but I was in a terrible rush and must have missed it when I focused on getting food in instead.
I didn't punish her or immediately put her away into the cage. But I didn't give her attention either. I just left her out another half hour and put her away unrelated later.