I doubt Buddy'd take it seriously.

So how did he manage to re-introduce his girlfriend and her father in the previous episode if that never happened in the future?And how do you know that a minor event holds no connection to a major event, like stopping someone going somewhere could stop his colleague get hit by a bus because he will cancel the meeting and that leads to a notable person in the bus to not dying.You get the point. So in my opinion, the OP has right to complain because he has no knowledge if his warning would maybe lead to another accident or whatever.:)

Your argument of... "Why didn't Sam just yell out, "hey! Don't get in a plane with the Big Bopper and Frankie Valle!!!!" as he leaped.... what a jerk, right? He just smiled like a moron.
and it made the whole episode almost completely pointless. "... holds no water in context of what this series is about. The major events that happened in reality are never changed. In the Lee Harvey Oswald episodes he wasn't able to prevent the assassination, because in REALITY that happened. What he "changed" was that the first lady wasn't also killed. Why, because in REALITY she was never killed; therefore she was a variable that he COULD change. Had he prevented the plane accident in the show that takes away from the "magical" aspect of the show that he was responsible for putting ppl on their proper paths and therefore "creating" the reality in which we actually live.This show did its best to not change our timeline, but to show assists that led to our timeline. In other words the stuck with overall historical reality, but altered the stuff that led to it to give them a fun story to tell.Or to put it yet another and more simple way...IT WAS A FLIPPING TV SHOW. THEY CAN'T really CHANGE ANYTHING AT ALL SO GET OVER IT!