re: DVD question
I get exactly the same problem here in Australia, so it's worldwide.
if you turn the DVD over you will typically see scratches, animal tooth marks, footprints, chewing gum, and lipstick on the playing surface of the DVD. Most peole seem to use them as coffee coasters or furniture rollers during the week they rent them! Scraping this material off adds immesurably to the viewing experience!
When buying ex-rental DVD's I give them a good inspection before accepting. For rental, I clean them well before loading into my beloved PC....