Said reference has since been removed, according to Square Enix.
However, Square Enix has since been in touch with TheSixthAxis to report that this is not the case.
“DRM-related text appeared incorrectly in the description of the digital download version of Tomb Raider on the PlayStation 3 in North America. It suggested that users were required to log-in to the PlayStation Network before each game session.
“This was NOT (and actually never was) the case; but the reason the text appeared was due to a small error in our submission documentation. The DRM notice was a part of standard PS Store legal text, and does not affect users’ ability to download or play the game.
“To relieve any confusion, the portion of that text has been removed. A user is not required to be logged into the PlayStation Network to play Tomb Raider (except to play multi-player). We’re sorry for any confusion that was caused.”
Thanks Square Enix! High five!