Nope, the guy and his girlfriend came back for her. I was heartbroken but was completely expecting it so I wasn't hugely shocked. I was, however, able to scare the girlfriend by telling them all the ways that Addie could possibly die due to their negligence. She does LOVE her owner though. Every time she sees him her tail starts wagging so hard and she runs up to him and starts jumping up at him. That makes the whole thing easier.
Anyways, she still comes over. It seems that no matter how hard I try to fill the holes and cracks that she gets in through the next day she will be sitting sweetly at my back door, staring at me and Dreizehn, and tapping the door with a paw as if saying, "Hey. Hey! Wana come out and play? Please come play with me!"
Really though, the guy seems to be taking slightly better care of her. She SOMETIMES wears a reflective collar (though never with a tag) and he got her microchipped. I'd love to see her spayed but it's a start. And this way I still get to see her because if I had kept her I was going to need to rehome her.