DQV for the DS had anti-piracy that made it impossible to continue past certain points in the game. Like in the beginning, you couldn't leave the boat, even after triggering all the needed scenes. I think things happened in pretty much every town you visited as well, events would not occur that were needed to continue on. You could still run around, talk to people, etc.
Even though I had a working rom, sometimes I thought the AP was still there because I got really stuck in a couple of places.