Walter Montego: If the Pond game is down to five people and this person was to move right after the start of the next round thinking they'd have almost two days before they'd need to make a move they'd be in for an unpleasant surprise if the remaining players were to all move right after the player had logged off and the round started right away.
But isn't this what happens on other games too? In a chess game with a one day limit, if my opponent moves immediatelly after my last move, I also only have 24h to move again...

There's a difference in ponds though: holidays and weekends don't count, so this may be a better explanation... but the "what if everybody moves right after you" kind of thing just won't be enough to convince me...