I'd say this: 

They know of their existence (They have access to earth's record after all).

But at the same time, they don't know what exactly to expect. My trio leaves all sorts of enigmas around, sometimes wondrous finds, sometimes completely useless and, in 95% of the cases, left mostly unattended with harmless automated maintenance.

Though the last 5% of times you know immediately when you step in a hornet's nest. That means drones swarming all over you, already firing their long range weapons the moment you enter the system.

As right now Keo's holding to actually trap them, I'd call this one a first.