Sense it seems everyone is throwing out ideas on rules lately I figured I might as well go ahead and do the same. Of course the idea a bring forth only effects the villages themselves and only those who rp the whole 'Village based RP' idea.
Anyways, I would just like to point out that I think that the villages have OP Barriers. I mean should we not be inspiring more rp and that usually streams from village attacks so why not encourage more of the sort.
I think any barrier that acts as an auto-hit or chakra manipulation should be off limits. For example the Chakra Eating Mist of Kiri, the Iwagakure Barrier that automatically places a seal on anyone who enters, the Power Release Barrier of Konoha, the Preta Barrier of Konoha, ect.
I think it should be limited to a sensory barriers and Canon Barriers such as the one Bocc uses, and the Chakra Chains Barrier I use. It should be a general rule of thumb you can't enter anther village via space/time ninjutsu, with the exception of being summoned.
Anyways I think you all get the idea. Let the villages be protected by those who say they are the protectors of the village, plus this makes infiltration and spying easier as well.