I have a DVD drive on my computer and on my PS2. I watch region 2 DVDs using the (unmodded) PS2. Any other region I watch on my PC.
I bought Walt Disney: One the Front Lines, a region 1 DVD, from Amazon. If I had watched it alone, I would have wathced it on my computer monitor. But since I wanted my friends to see it as well, I hooked my PC to the TV. This is where the problems started.
I tried to use PowerDVD to watch to movie, like I normally do, but it wouldn't play the movie, because my TV-out doesn't support Macrovision. Then I tried using Media Player Classic, but it said that the DVD had the wrong region.
About half an hour of googling later, I found a solution that worked: VideoLAN. We wee finally able to watch the DVD that I paid money for.
All these problems were caused by me paying for a movie. If I had just downloaded an Xvid DVD-rip, or a DVD image from the internet, or even ripped the DVD to an image on my hard disk, I would have had no problem playing it on my TV.
That is the reason I don't like copy protection schemes. They always screw the paying customer but do very little to stop actual copying and distribution.