re: HD 188015 b
Similar reasoning makes me think there's a non-zero probability that Europa (or Titan?) could also have intelligent, non-technological life in their oceans. If there is intelligent life there at all, it will likely have been intelligent for a much longer time than us, and therefore probably more intelligent.
And so we can't let them get their tentacles on our technology, because they'll easily conquer us - our only chance would be to kill them all if we discover they exist.
(Kidding, mostly, about the last part of this post.)