Actually you can shutdown the miniMAD via the Q key of your usb keyboard.
Yes of course. But it is necessary that a click to click. I mean scheduling a power-on schedule (from the same madmapper?) Or with an additional script for shutdown. So an operator is not required to do the task.
normally it is ok, never had problems, but you never know. we put the system on a read only partition to avoid this problem as much as we can, but data corruption CAN happen eventually during hot unplug.