Imagine another direction S2 could take, where instead of merely siding with one person or the other, such as Kenny and Lily, you're forced to choose between two survivor groups locked in mortal combat.
Suppose for a moment if the game HAD allowed you to leave with Lily in the RV, and the entirely different course you could have charted for episode 3. Not just alternate dialogue or relationships, but alternate environments and settings. Now, crank that up to a larger scale, where two survivor camps are locked in war over supplies or something similar. Which group would Clementine join under the circumstances?