The by law "Owner" is too broad, you were a guest at the tim

You were the quest at the time.  The rule is not to have residents occopy the quest parking for long length of time, given limited space.  The "Owner" should mean the residents, not the property owners if they don't live there.  You certainly can reason with the HOA and I guess they can wavier the fine in your case.  Remeber the rule is there for a reason and everyone should obey.  Of course there are exceptions and that what the hearing is for.