error on I-rule

I saw a good point elsewhere that it's better to have no default Pool on the VS because if the default Pool fails and the VS goes down, the iRule won't trigger and the second Pool won't be used. With no default Pool the rule would look like this;

when HTTP_REQUEST {
 If the preferred Pool DOES have Members
 if {[active_members [LB::server primary_pool_name]] > 0} {
  Use the preferred Pool
  pool primary_pool_name
  Stop processing the iRule for this event here
  return
 }
 else {
  Otherwise, use the secondary, back-up Pool
  pool secondary_pool_name
 }
}