The switch to Ethan was to accomplish a few things:
1 - it teaches Adam a lesson that he shouldn't go running his mouth
2 - it prevents any idol play now that the target is known
3 - it keeps both Rob and Parvati as shields for future votes (which is what I think Adam is trying to do but obviously quite poorly)
The flip side to #3 is that it's clear that a tribe swap will happen. Maybe not soon, but it will happen before the merge. And with enough pre-existing relationships and "known strategies" you can bet that the votes won't necessarily fall on tribal lines
1 - it teaches Adam a lesson that he shouldn't go running his mouth
2 - it prevents any idol play now that the target is known
3 - it keeps both Rob and Parvati as shields for future votes (which is what I think Adam is trying to do but obviously quite poorly)
The flip side to #3 is that it's clear that a tribe swap will happen. Maybe not soon, but it will happen before the merge. And with enough pre-existing relationships and "known strategies" you can bet that the votes won't necessarily fall on tribal lines