I've heard the experiments the Malnosso conduct on the village are done with the intent of testing shift technology. Though I can't say for certain whether that's something that directly relates to how people come and go from this world or not.

There was an experiment in this past year where people were sent home for a day and others were sent to different worlds, but the effects weren't permanent. We were told upon returning to Luceti that our presence left no impact, so it was as though we never really went there at all.