You answered that question
yourself between posts #3 and #4..."Now, you would expect
the next time I load a synth, MIDI output would NOT be on by default, correct?"
No of course I would not, and if you would bother to read what I wrote (and after doing so attempted to understand it),
you wouldn't either. Please, for God's sake, read this:
EVERY TIME YOU INSERT A SYNTH WITH MIDI OUT, IT SENDS A FLAG NOTIFYING THE HOST THAT IT SHOULD ENABLE MIDI OUT. SONAR DOES NOT INITIATE CHECKING THE BOX. THE INSTRUMENT INITIATES THIS BY ASKING SONAR TO CHECK THE BOX, AND SONAR FOLLOWS THE SPEC SO IT DOES. THE CHECKBOX IS PROVIDED SO YOU CAN UNCHECK THE BOX AND CLEAR THE DEFAULT. And one more time...if you want SONAR to do something BEFORE the instrument is loaded, you need to submit a feature request that asks SONAR to act pre-emptively
prior to loading a synth so it will ignore the default it is asked to create by the instrument and the spec.
I realize you are a "my mind is made up, don't confuse me with the facts" type. But I'm sure 99% of the forum members here understand what I said. Perhaps one of them can explain how it works in a way that even you can understand...although it won't do you any good if you don't read their posts.