Generic "Sending to Device" template not kicking in on Folder Device
According to the configuration dialog, it says "Here you can control how calibre will save your books when you click the Send to Device button. This setting can be overriden for individual devices by customizing the device interface plugins in Preferences->Advanced->Plugins"
So I took this to mean that if I don't specify anything on the device specific plugin, it would use the template specified in "Sending books to devices".
At least for the folder device this does not work. You actually do need to specify the template in the folder device plugin or it simply will not work as intended. I did get the name elements I wanted but it did not create the folders, instead it replaced the forward slash with an underscore, creating all files in the single folder.
Only after copy/pasting the exact same template in the "Configure this device" dialog did the folders get created according to the template.