heh.. here is the response i got.

  Hi there,
 
  Thanks for taking the time to write in to Dropbox Support. My name is Ross, and I will provide assistance with your case.
 
  From my understanding, you are inquiring about being opted into Dropbox AI by default.
 
  Thank you for alerting us to this problem.
 
  Dropbox engineers are aware of the problem and are working on a solution.
 
  Also, please note that no files were shared in this case.
 
  Sorry for any inconvenience this is causing.
 
  We'll update you shortly on this issue.
 
  Don't hesitate to reach out to me again for further questions!
 
  Best regards,
  Ross