This is just an extension of the current General ability to assign militia. Once they are assigned, they aren't militia any more. It also requires a noble that doesn't currently have a unit, or in the 2nd case, only really allows the Lord to quickly grab a unit if they have lost one.
My only though is, is it exploitable. Given time a Lord could recruit and station several top notch units. Then when war comes they are easily able to refit when their unit is dead. This would be balanced by the cost of maintaining the militia, and the fact that militia units lose men over time. Can't see that it would be worth the effort personally but someone else might be able to provide more info.
Militia units lose men over time?
