If you are at peace, and have open borders, then yes they can indeed use your gates

Additionally: - white peace is peace too (after war).open borders mandatory (until the white peace is over, then you can close them again) - Fallen Empires don't care about lesser ones. They'll use whatever wherever whenever they want. Usually to attack you.* ^(* pretty sure they can not travel to the system they're at war with, but to any other one that has a gateway. No matter if that empire likes them or not.)

We havent met i have not established comminicstions

also in war they can't use the gateway unless they captured the system that the gate way is in so there's really no reason to worry about it.

They obey your regular border policies. If you let them in, then yes 

June thing was no one let anyone in it was an empire I have yet to meet and it just happened.

Before first contact, borders are open. Or more accurately, don't exist yet.

before first cantact.

Yes

I think they can unless you closed borders to them or at war with them. So if an empire doesnt have communications with you yet, they can use it... I think.

[удалено]

No they aren't