Address "portability"

What is the general consensus of this group regarding the "portability" of
addresses in the 204/8 and 205/8 range?

  All address prefixes are portable. Their routability by any
  given transit provider is always suspect and varies from time
  to time.
  This nomenclature has been foisted on the unsuspecting by well
  intentioned people. This idea fosters the myth of global
  reachability for any given prefix.