So, it is not uncommon to have to temporarily unmanage a node for maintenance.
How bout adding "Unmanage" on the right-click context menu, when right-clicking on a node?
This is a lot quicker then selecting the node and unmanaging it from the node details.
What say you?
Now that was easy..
If you use the Node Management page you can basically do this in addition to un-managing multiple nodes at a time.