I7: Why is latest rule result assignment hardcoded at the end of rulebook routines?

The end of every rulebook routine has a couple of lines like the following:

	latest_rule_result-->0 = 0;
	return 0; ! 4 rule(s)

The intent seems to be to set latest_rule_result-->0 to RS_NEITHER if no rule in the rulebook has made a decision.

However, routine FollowRulebook() also has this block (after setting rv to the value returned by the rulebook routine):

    if (rv) {
            #ifndef MEMORY_ECONOMY;
            if (debugging_rules) {
                    process_rulebook_count = process_rulebook_count - debugging_rules;
                    if (process_rulebook_count < 0) process_rulebook_count = 0;
                if (latest_rule_result-->0 == RS_SUCCEEDS) print "[stopped: success]^";
                if (latest_rule_result-->0 == RS_FAILS) print "[stopped: fail]^";
    } else {										! <-- rv == 0
            if (debugging_rules)
                    process_rulebook_count = process_rulebook_count - debugging_rules;
            latest_rule_result-->0 = RS_NEITHER;	! <-- set latest_rule_result-->0 accordingly

It does not seem necessary to make this assignment in both places, and the ones in the rulebooks seem superfluous. Is there a reason to make the assignment at the end of every rulebook like this, or is it something vestigial from an earlier iteration of the rulebook system?