Originally Posted by PayItForward

Yes, passenger of size are encouraged to get seats up front or if in economy, two seats. However, they are supposed to call in and I think the ticket is issued not as 2 x Pax but differently. This also ensures the two seats are never separated (which defeats the purpose for extra space). OP is buying two tickets under his name on the same flight. One ticket could be cancelled by the system since it is clearly the same pax with the same SM account.

http://www.delta.com/content/www/en_...eat-space.html