I'm getting some strange behavior. First, I am assigning the File Handler to Explorer for layer packages here: C:\Program Files (x86)\Common Files\ArcGIS\bin. Then, when I double click, the first time, I typically get an error and Explorer eventually opens with no data. I can see that the package is unpacking, however. Then, if I double click again, sometimes it opens successfully and sometimes nothing happens. I'll let you know as I find out more.