It's a risk that can be easily minimized: You can run a scout unit
down your intended path, and you can use NEUTRAL to stay away from any
large forces that you know of.
There's still a possibility that you can run across some large,
unexpected force and attack it disastrously. But any unit in Olympia
runs the risk of being involved in a disastrous battle with a larger
stack. Especially one that is being actively hostile. So I don't see
that as a particularly huge drawback. If you adopt a policy of
HOSTILE ALL, you'd better expect trouble at some point anyway.
I see this as a possible compromise: Let GARRISON units have HOSTILE
ALL. That permits a sort of "border control" without turning Olympia
into "Avoid the big auto-killer stacks." Even better would be some
kind of turn format indicating that (if the GARRISON unit is HOSTILE
towards you) you can't enter the province without ATTACKing the
GARRISON -- rather than letting you move into the province and then
having the GARRISON auto-attack you. So that you'd have to use ATTACK
to move into a hostile province.
-- Scott T.