Airlines don't comp you as a reward for flying a lot with someone else in the past. They do it in the hope that you'll fly a lot with them in the future. It can help to have a credible story as to why this will happen. It can also help to have a travel agent or corporate travel coordinator request it through his/her airline sales rep.
(edited to clarify wording)
[This message has been edited by Efrem (edited 09-23-2002).]