You are serious and I can't believe what I am reading. HOW do you know whether they have started planning or not? WHY would they tell you or the press demons? According to your logic they won't get married because YOU are not entrusted with the details of their marriage... Words fail me.
They are engaged, Sarah Palin said that they will get married. Their word is good enough for me. It should be also for you.
Rather than consuming bandwidth on a topic of no importance to anyone but the families and friends, let's just drop the matter. If they eventually decide to marry each other, fine. Best wishes to the young family. If not, well, that's their business.