I agree that only those organizing or with a real need of financial support (folks from developing countries or from non-profit orgs or some students without substantial resources) could have their admission fee waived or reduced, all the rest MUST pay, even if you give a talk or serve in other capacity. As others said you are doing a "public service" to the rest of the community and if you give a nice and valuable talk you will get the recognition of the NANOG community and your colleagues, and we can put into consideration including a gold star sticker for your service. It will be really unfair for those paying (even if their companies do it for them or don't care because they have a mountain of cash) if there is a special benefit for some so they don't pay. My .02 -J