Re: Cause and Effect - why didn't they...
Oh, we all know what would have happened. Picard would be the one to give the warning to the past due to his incomparable elocution skills with important speeches, and it would have gone like this: "Attention, this is Captain Jean-Luc Picard. The information I am about to give you is of high importance and necessary for the safety of the Enterprise. It is absolutely imperative that you immediately-- ." Boom.
Dr. Howard, Dr. Fine, Dr. Howard: For Duty and Humanity!
--Men in Black, 1934.