Best case scenario

The origin of words and sayings can be interesting and thought-provoking. Take, as an example, "best case scenario". Did this have a meaning before the advent of "Deal or No Deal", the television program where a contestant has to choose a single case from many - each of which contains a $ amount from 50 cents to $200,000 (Australian version). They then have to open the other cases - and depending on which amounts are revealed, they are made an offer for their case. As an offer is made they have two options - "deal" or "no deal". The object of the game is to end up with a sizeable amount of money - either by making it to the end with your case being the one to contain big dollars, or to make the "deal" along the way - to sell your case, with whatever it has, for the offer. It was in yesterday's program that the presenter, outlining the possible options to the contestant with $2,000, $5,000 and $50,000 still in play, used the phrase "the best case scenario". So where does "best case scenario" come from? Did it ever refer to physical cases (aka ports, bags, suitcases) or does it relate to case as in "proceeding in a court of law" or "a problem requiring investigation" ... or something else entirely? According to the SlovoEd (Palm version) dictionary it's: being, relating to, or based on a projection of future events that assumes only the best possible circumstances [a best-case scenario]. Somewhat surprising, in a quick search on Google for "best case scenario" three of the first 10 results show (in bold print) "worst-case scenario".