In the past, the UN has stayed out of the internal affairs of countries unless invited in.

在过去，除非受邀请介入，否则联合国不参与各国的内部事务。

《柯林斯英汉双解大词典》

He will not come unless invited.

除非邀请，他才肯来。

youdao

I won't go to his party unless invited.

除非被邀请，否则我就不去参加他的晚会。

youdao

The latest draft requires troops to pull out by June 2011 unless invited to stay by Iraqi leaders, officials said.

BBC: Iraq mulls new US security draft

It is opt-out, of course, because an opt-in to browser tracking would require universal cooperation from all industry players to stay out of our computers unless invited.

ENGADGET: Editorial: We, the digitally naked

And if you're a contractor or part-time employee, don't show up to the party unless you are specifically invited by your immediate supervisor.

WSJ: 'Don't Cleat the Boss' and Other Tips to Manage the Summer Office Picnic