Hard to imagine but I had not actually tried running the sample code I was working from, assuming it worked how I wanted it to...anyway as it turns out the sample also COPIES and doesn't move, so whatever I am doing is working how it's supposed to, it's just not how I want.
Let me approach this a diferent way: if I use the default drag and drop behavior of the TileList (which does what I want), how do I find out which item was dropped and pass that info to a web service call?

