Our best guess as to how folks from other worlds would treat us may be to see how we treated folks who don't resemble ourselves. Although we regard ourselves as kind, generous, considerate and so on, let's check that with reality.

On an individual level we can be all of those things. On a group level we've abused African-Americans, Mexicans, Middle Easterners and on and on and on. And that's within our own species.

Nope, anything different from "us" is abused. And we should assume another intelligent being with the technological tools necessary to get here would react to us the same way.

Hopefully we'll stay like a submarine, stealthily quiet, sensors alert, taking in our surroundings but not revealing out presence.