New Video releases

Does anyone know where the practice came about of releasing new movies for retail (Rentals, DVDs, Videos…I believe even music CDs fall into this pattern) on Tuesdays? It doesn’t appear to be a binding rule, since every so often a movie will come out on another day (Scooby Doo is the last notable exception I can recall, came out on a Friday), but it certainly appears to be the industry standard.
My sister is a manager at Blockbuster, and no one there seemed to have any idea either. We were able to come up with a few ideas, mostly speculation revolving around rental periods and weekend availability, but there were far too many variances to make a satisfying answer. Any ideas? Is this done in other countries as well?

Oren

My guess: Tuesday is a slowday in retail and therefore the employees of the store would have the most free time to put out new stock. Most of the new stuff comes in the week before and just sits in the back waiting to get put out on Tuesday.

Distributors pick a day in the week and plan their entire year around the [first] [Tuesday] of the month. That way they have a set deadline, like magazines, and everyone knows it. It makes things easier all round.