CIX Filtering...

Does anyone remember when the CIX proposed to filter networks of customers of CIX members which were not themselves CIX members? Was it as early as 1995? (We are trying to review a paper on Internet exchanges. It seems ironic that this effort by the CIX to restrict traffic was rendered ineffective by the same technique the CIX used to overcome the impediments created by the NSFNET AUP, namely alternative paths for "unacceptable" traffic.) Thanks, -tjs