Scientist Stephen Hawking is convinced that there is alien life elsewhere in the universe — mathematically, it just seems likely — but strongly recommends that we not look for them. He envisions a situation where a nomadic race of aliens might raid the Earth for our natural resources or a “Columbus discovers the New World” scenario where the friendly welcoming natives get wiped out by disease or violence. Hawking therefore adopts the “pessimistic” view of extraterrestial contact where marauding aliens who find us would be perfectly happy to wipe us out. (The “optimistic” view, epitomized by Star Trek, posits that any aliens intelligent enough to cross interstellar space are intelligent enough not to be bloodthirsty mass murderers.)
In law school we called the Hawking approach “foxholing.” If you hadn’t read the case and weren’t prepared you tried to stay out of the professor’s line of sight and hoped he wouldn’t call on you. If the technique worked, you made it to the next class without undue embarrassment — but I always thought the better approach was to be prepared in the first place.