When I was playing the demo I made a note of the time I started and made sure I paused the game and exited exactly 59 minutes later. I'd been forewarned by similar happenings in other games.

Mind you, I didn't have long to wait for my unlock code, so my villagers might have even survived without me. In fact, I think the first couple of times I played I suffered wipe-outs, so they couldn't do much worse.