Richardson said:
Does changing the values of misc.txt affect human and ai players alike?
All players
And what about events, if there is a "random = yes" statement on the event, what is the likelihood of the event firing? Can that be changed?
IIRC random events work like this.
Every country is assigned a different random event (at random).
Once the conditions for that event are met the event will fire and a new event (not already assigned to another country) will be assigned.
It is possible for the same random event to be assigned to replace the one that just fired.
It is also possible for a random event to be assigned that will never fire (i.e., requires a specific government type), if so this government will never have a random event fire (until/unless you save reload).