Too much SciFi...

I think Stephen Hawking has been watching too many re-runs of V.

He's reportedly saying that if an advanced extra terrestrial race came a knocking then their intentions would more than likely be nefarious as their advanced technology has used up resources on their home planet and they'd be coming to pillage us of our planet.

I think he might be forgetting about the evolution of morality in sentient beings.

If I was an advanced sentient being and had used up all my resources, I'd like to think that I'd propose that we pillage some planet that isn't home to developed beings. That said, there would be a bit of a grey area as a planet that had sufficient and relevant resources would more than likely also have some sort or developed life. Where would the line need to be drawn.