Lots of google searches.
But the Crux of the loophole is since Best Buy is third party reseller. Once u upgrade via Best Buy. Best Buy will notify Verizon to extend your contract for 2 years.
The "data plan change" authorization is tied into the nano sim that ships with the iPhone I ordered. All Best Buy cares is I "activate" the phone. Once phone is activated Best Buy lets me off the hook and confirms with Verizon system the transaction is complete.
Verizon system doesn't know the nano sim that ships with the new 6S that will trigger the force data plan change was never activated. That's the key.
It's a little confusing. Google it.
1. Order upgrade from Best Buy. Best Buy confirmation even says "keep existing plan". If someone goes wrong you can always return the phone to Best Buy with no restocking fee within 14 days and get ur unlimited data back
2. Receive phone. DO NOT TURN PHONE ON. Take an already activated nano sim (presumably your Verizon active nano sim from ur phone you been using ) and put it in the new 6S.
Take the nano sim that was preinstalled out and destroy it. Yes. Destroy that that nano sim. Because you never want anyone to use that nano sim that's tied into your account that will trigger the data plan change.
You are good to go.
The reason I went with the 6S over the 6s plus was I didn't want to risk having to wait 2-3 weeks for the 6S plus. Time is of the essence here. Either your contract needs to be extended before the October 15th "notification period" or November 15th date.
Since my billing period ends October 17/18 (can't remember which one). That means officially Verizon can say they inform me that date in the billing insert my data price would change. And that's the 30 day notice.
This is the detailed link other methods to keep unlimited data.
http://slickdeals.net/f/6964624-upgrade-and-keep-your-unlimited-data-with-verizon