That has a very high risk of stalemating the game, and increasing refleeting time. Also, micro managing starship is mandatory if that's in.
I like that it forces the player to leave his territory though.
How about tugs would bring "something" back from the AI territory, like the core of a guard post, or just a blob of metal that would act as salvage, to make refleet go faster ? (I think chemical art suggested that in another thread).
It'd fit with "guerrilla" style of AI war, blow stuff, take stuff, go back home, repeat.