For many places you are asked for a name and a location.
Stayed with the promocode at Radisson BLU Scandinavia in Oslo from 14th january `12 and was just asked for the name and location of one of my carlson friends. Was even upgraded to business room with no extra pay. Breakfest is also included. Price 625 NOK / 90 USD.
In addition: CAREMPRT is an even better code, but then you need a form from a friend of you. This equeals to travel with an ID ticket in an airline company.
PS: I do not work for Carlson but know people in this great company