route-set members

Dear Colleagues,

I have a simple question about route-set objects.

<--RFC2622-->
 ...
 5.2 route-set Class
 
   The attributes of the route-set class are shown in Figure 12.  The
   route-set attribute defines the name of the set.  It is an RPSL name
   that starts with "rs-".  The members attribute lists the members of
   the set.  The members attribute is a list of address prefixes or
   other route-set names.  Note that, the route-set class is a set of
   route prefixes, not of RPSL route objects.
 ...
</--RFC2622-->

 1/ What is the reason that a route-set member can not be
    an aut-num or as-set object ?

    Because some registries allow this:

    route-set:          RS-AS101-TO-ABILENE
    descr:              routes that Abilene should accept from AS101
    members:            AS73, AS11808, AS7774, AS3807, AS13476, AS11995,
                        AS14077, AS13476, AS11964, AS11827,
                        131.107.151.0/24, 131.252.0.0/16, 134.39.60.0/24,
                        161.55.0.0/16, 168.156.80.0/20, 168.156.96.0/19,
                        192.35.180.0/24, 192.46.80.0/24, 198.107.144.0/21,
                        198.32.40.0/24
    admin-c:            UW-NOC
    tech-c:             UW-NOC
    mnt-by:             MAINT-AS73
    changed:            aracine at cac.washington.edu 20010426
    source:             RADB

 2/ Means the last phrase that there are no necessary is
    to existence of a related route object ? 
  


cheers
frank