I agree with Basalla; however, I'd quibble about interstellar conquest. We've had radio for about a century (Tesla demonstrated radio controlled mini-subs in 1893's exposition in Chicago) and have been broadcasting commercially and militarily since the 1920s -- and haven't worried about whose ears our signals might reach.
If SETI were to succeed in finding a signal which is both generally accepted as the product of an intelligence, and its location could be determined, we'd have no way to achieve interstellar flight to go check 'em out. :') I'm not deterministic when it comes to technological and scientific developments, but I'd hazard a guess that radio etc precedes interstellar capability in any ET civilizations (if any are out there).
It is not our being able to check them out that would be the problem. It is their ability to check us out that we should be concerned about.
Change the paradigm to submarine warfare. Rarely do you use active sonar, as the element of surprise can greatly determine the winner of an engagement.
If you broadcast your weakness and inability to bring the fight to your opponent, he will exploit your vulnerability to suit his goals. To assume that he would do otherwise is illogical.