If we support ejecting on halt, then we can relatively easily eject the livecd on shutdown without having to worry about things going away and leading to read errors. Patch attached and I've sent it upstream for comment as well
Created attachment 307129 [details] upstart patch
Created attachment 307131 [details] initscripts patch And just so it doesn't get lost, attaching the simple initscripts bit too
This bug has been triaged
I closed bug 239928 that depends on this since it works on the F10 Snap2 Live CDs that I tried. I'm not sure of the actual implementation, but it appears that this bug should be closed too. If someone feels otherwise, feel free to reopen it :-)