So far in every game I've played the precursor ranger event has happened multiple times (the one where you or an AI get a ridiculously overpowered ship). I usually get one first, then at least one AI gets one - and this is still early in the game (since I've yet to come close to running out the tech tree in any game).
It's ridiculous when you're researching techs to get an attack 3 weapon, taking 10 weeks, and your best ships are 12ish/4ish, and you and AIs are getting these 66/24 rangers like candy - in each and every game. Getting ONE of these (me or an AI) once every 5-10 games would be plenty. As it is, it's a given, not random.