more obviously distinguish your VMs from group ones

If you get a message about being out of running memory quota, the natural instinct is to shut down all the machines you're not using, and apparently people don't look carefully enough to distinguish personal machines that can help with quota from group-owned machines that can't -- they all have the same green glowing power button.

This used to be a huge problem in the xvm-dev days when people on xvm-dev would click all the off buttons they could in an effort to get more space, and shut down xvm.mit.edu, and make themselves and everybody else sad. I think these days we hack around that particular issue by hiding the sysvms from the web interface.