MPLS VPN design - RR in forwarding path?

Hi everyone, I'm reading Randy's Zhang BGP Design and Implementation and I found following guidelines about designing RR-based MPLS VPN architecture: - Partition RRs - Move RRs out of the forwarding path - Use a high-end processor with maximum memory - Use peer groups - Tune RR routers for improved performance. Since the book is a bit outdated (2004) I'm curious if these rules still apply to modern SP networks. What would be the reasoning behind keeping RRs out of the forwarding path? Is it only a matter of performance and stability? Thanks, Marcin