(Rails 2.3.2, OS X 10.5, MySQL 5.0.x)
I have combed through all my callbacks, even commented them out. Nothing in there appears to be the problem (nothing forcing a save that I can see).
"Adding an object to a collection (has_many or has_and_belongs_to_many) automatically saves that object, except if the parent object (the owner of the collection) is not yet stored in the database" (http://api.rubyonrails.org/classes/ActiveRecord/ Associations/ClassMethods.html)
Fred
