you can’t avoid combat completely
naval units (besides submarines) are still not allowed to enter a hostile sea zone without attacking
in the case of building units in a hostile sea zone
it does not apply to open sea zones at all
in OOB there are no other situations where you can start in a hostile sea zone (1. enemy built naval unit in your sea zone 2. submarines submerged)
in AARHE there is one more situation to cater for, “retreat via break-off” in naval combat
what I dont like is how the enemy can build a naval unit in your sea zone and not start combat
and then when its your turn you must get out or start combat
(for the strategic advantages such as waiting for reinforcement or simply the defence values being better than attack values, of course this partially eroded under AARHE, its mainly the air units left that are better on defense)