Multiple people have stated that their VZW account pages showing that they have renewed the S3 on contract have confirmed that unlimited remains.
People who are getting this phone in hand this morning are receiving contractual paperwork confirming their unlimited.
At least two of these people called Verizon this morning to make sure and were told that they could keep unlimited - one of these people had a CSR who made a mistake and kicked him off unlimited and yet the people at VZW were able to manually migrate him back to unlimited within minutes.
VZW's own Twitter feed stated on multiple locations that if you pre-order before 6/28 that you can keep unlimited.
Relax, OP. You'll be fine

Now can we please put this conspiracy to rest already?