One of the more amusing tales of science fiction is the one where the exploring earthlings, who believe that technological survival requires logic and logical beings can’t be warlike, run smack into an alien warship whose star troopers proceed to eviscerate them. (See Larry Niven’s warcats.)
Comes now a similar argument from New Scientist (“Hello ET, We Come In Peace”) that we need to pour more tax money into the Search for Extraterrestrial Intelligence. Why? Because we need to let any other cosmic civilizations know we’re around. (Like why should they care?) But is that so smart? We might just be inviting some really big trouble to come calling.
THE TEXAS SCRIBBLER 
Yeah, SETI is just fine – but, please, let’s us just listen, not broadcast. Our planetary radio signature should be just fine, thanks a lot. Besides, there’s not anything we can do about that – retroactively, and all.
jd
Yeah, it’s probably too late. But no sense in making it worse. From what we know already, there’s not that many habitable planets available. No sense in inviting someone to come take ours away from us.
On the other hand, we may encounter some groovy kinds. Its’ hard to find someone worse than we are already…
So long as they’re not superior in technology. But if they come here first, well, we’ll have to assume they are.
If they come I doubt it’s just to say, “Hi”.
Hopefully they want to trade.
But I’d bet on “Euro-style colonialism” with a side bet on “Humans taste good”.
At best, they might decide to turn Earth into a zoo for interstellar tourists.