Makes sense and I understand the desire not to have empty hostile systems running on the turn-timeout.
Actually locking my systems vs the rip tides isn't easy, theres a few other home systems very close to mine which I believe I can't do anything about so its not too easy to form a centralised base around my home world, tho if i were to spread north a long way theres absolutely no home worlds up there.
Of course having the single low-cost unit in the system forces everything to be turn based on the global time out anyway, which would really suck if i were to stop playing as people would have to hunt through the systems for a bunch of now silent-running frigate class ships spamming beholders all across the system (which is going to take months to find then kill the ship lets face it).
The only idea I had in mind would be something like a new construct, a "Temporal Protector" or something - come up with a better name - which 'holds' the turn when a hostile jumps in for say 2, 3, 5 days from the point at which the hostile enters (take your pick, 5 day turns are too slow for my liking anyway but I guess you have picked the duration with a particular audience in mind). However the act of 'disrupting' the turn destroys the protector so if you haven't ordered reinforcements into the system within that grace period of 2-5 days the protector will be gone and future turns will proceed at the hostile's leisure.
Think of it like a 'you want this system? come make a stand for it, otherwise you default it' kinda approach rather than my present 'lock the system with a token ship' thing (which i'm not liking

)
Just a thought, you did ask
Cheers