Any sufficiently advanced technology is indistinguishable from bullshit.

Maybe they have tech that shows them our radar scanning patterns, so they know where to be.

And maybe other tech to make themselves less visible via vision, ie, light bending or something like that.

They might want to see how humans react to the possibility of aliens, without completely freaking the planet out by landing somewhere, walking out of a ship, and saying "take me to your leader".

Once in a while we send a bathyscaphe or two to the deep to explore the oceans bottom and the lifeforms there. The conditions there are unsuitable for us, and it takes a good deal of effort to make those expeditions. The strange lifeforms in the deep observe the occasional spherical objects that briefly enter their habitat and then mysteriosly disappear. If our science advances enough, we'll establish a research station there, and maybe even a colony if we find something valuable on the bottom.

> How do they know exactly where to be

savegames

> But why do it at all?

Why ... there's no needin' to explain a "fuckin' with" ...