Another interesting fact I hadn't noticed before:

Bad personal events do not happen in the last two rounds.

Some more details on global events in PlanetM.U.L.E. 1.3.4:

Planetary Pests and Radiation can only apply to the #1 player (this may be an off-by-one bug in the code, since I think the intention was for them to affect #1 or #2).

When a quake occurs and the mountain-moving coin toss passes, a mountain may only move if it is owned by no one or the #1 player, and it has a plains beside it. Of the mountains that meet this criteria, the game will prefer one that can move to an unowned plains.

When cutting plot production in half for a quake, round down.

A crater produces like a plains with 4 crystite. A meteor can theoretically strike the same place twice.

It is possible for no event to occur in the following circumstances:
1) Planetary Pests was selected and the leader has no food M.U.L.E.s
2) Radiation was selected and the leader has no M.U.L.E.s (unlikely)
3) Sunspot was selected and no player has a Solar M.U.L.E. (also unlikely)

[more]

My family is fairly new to M.U.L.E., so maybe we just aren't experienced enough to handle a lost plot as people are suggesting here. But we were finding the "lost plot" event way too discouraging, especially in early rounds. So, I did some hex editing and eliminated it.

The result was surprising - not having these events actually made it more likely that someone would lose interest in a game. Without the hope that something really evil might happen to the leader, there is less reason for the other players to want to keep playing. Also, without this very significant bit of randomness, it became far too predictable how the game would play out - it was almost guaranteed that the strongest player (my wife) would always win.

So, my experimental results, in opposition to my original hypothesis, would seem to confirm that (surprise, surprise) the programmers of the original M.U.L.E. really did know what they were doing.