Since we don’t know what they need and what their morality is we are safer not contacting them.
After all, it could be chocolate.
I don’t disagree.
My point is addressing that invading for mineral or biological looting does not make economic sense.
Invasion to simply take over the planet for colonization is the only reason that would make sense.
The biggest danger is that of cultural colonization in my opinion. (Look up the cargo cult)
Too late.
Anybody who could transport a battle fleet between solar systems has the ability to travel faster than light and to build and operate a propulsion system that would generate more power in a second than has been generated in the complete history of the Earth.
They would also need to be able to turn pretty much anything into food and water, because even at the speed of light, they have to feed the entire battle fleet for four years if they’re coming from the nearest star.