Bad polymorphism - Me, my wife and my PC

interface WithOpenPC {
}

class ForWork implements WithOpenPC {
}

class ForHobby implements WithOpenPC {
}

class Me {
  public WithOpenPC whatAreYouDoingWithPC(){
    if(isIDEOpen() || isBrowserOpen()){
      return new ForHobby();
    }else{
      return new ForWork();
    }
  }
  ...
}

class MyWife {
  public void checkOn(Me husband){
      // This is supposed to cause compilation error! 
      // at least, ClassCastException!
      PlayingWithPC whateverItIs = 
        (PlayingWithPC)husband.whatAreYouDoingWithPC();
      complainTo(husband);
  }
  ...
}