I'm thinking about a special protection system for PVP maps.
Idea is to make players build strongholds to protect their wealth and body.
In protected area, nodes are still digable by every one but:
1 - With a very low efficiency (maybe 100 times less efficient than unprotected nodes);
2 - Only when owner is connected (avoid offline players building demolition);
3 - Sends a warning to the owner when his/her protected nodes are being dug;
I'm not sure it is possible to code #1.
This means that minetest.is_protected should always return false (easy) and that tool efficiency or node hardness should depend on whether area is protected or not.
Do you have any idea of feasibility of this last aspect?