I was most interested in real-world experiences ("this happened to me
once...") so I could get a flavor of what to expect with the FAA.

Unfortunately, given my experience it's too late to do anything but get
an attorney and hope for the best. Once they've gone as far as setting
the penalty, it's pretty much too late to do anything else. They're
not going to back off now, and your chances of prevailing in
administrative court are low.

Remember, you are considered an interested party. Despite all the
experience we have with FAA inspectors out to get people, the inspector
is considered impartial. Therefore, if it's your word against his,
you're not going to win.

Michael