A discussion in this thread got me thinking about something else about this episode. Janeway makes the decision to not go back 20 years in time because "It would pollute the time line to such an extent that the consequences would be unimaginable". That's clear, yes. I suppose the same argument would hold if the wormhole would have lead back not 20, but only 2 years, since they still would have come back to a point in time before they left and, for example, could convince themselves to avoid their DQ adventure in the first place, altering history significantly. But what if they had found a wormhole with a 2-year difference in the 3th season? They would go back 2 years, and arrive at earth at at time they were lost in the DQ. None of the actions they would take would alter history that much compared to the case in which the wormhole would not have had a temporal displacement at all (i.e. it would simply transport them to the present AQ). But technically, they still would be altering the past. In short: where would the dividing line be?