Last night I was watching an ASA men's softball game. A batter had earned a walk, however he thought he was out. He walked all the way back to the bench. The defensive team appealed and threw the ball to first. As the defense shouted at the ump, the man came back and went to first. The umpire, puzzled by the situation, decided that since he did not see the man go back to the bench, he should be safe. I immediately saw that as the wrong call, once a batter/runner leaves the field or base line he should be out. After further thinking, I am having trouble with the call because if a batter earns a walk, he has a right to first base, once he gets there, he's liable to be out. What does anyone else think?

Memory don't fail me now...
 

It has been a few years since ASA. But... I believe a BR cannot back away from advancing to 1st (can stop but cannot back-up).

Sounds like the runner gave up his opportunity to advance and should have been called out when he first abandoned any effort to advance.

FED rules are different. 8-2-4 "The Batter-Runner shall be called out when: The BR fails to advance to first base and enters the team area after a batted fair ball, a base on balls, or on a hit batter... [therefore not out until the BR enters the dugout area].

Someone will correct my ASA interpretation if wrong.
:)

Was this fast pitch or slow pitch?

If slow pitch, the ball was dead so the batter-runner was not out. (caveat: I don't call slow pitch; there may be some divisions of slow pitch were the ball remains live. Mike Rowe can clarify.)

If fast pitch, the batter-runner should have been called out as soon as he entered dead ball territory (e.g. team bench). No appeal was necessary.

However, the umpire could not call that if he did not see it.

If fast pitch, bad call for what actually happened, but a good call for what the umpire actually saw.

Why didn't he see it? That's another question!

Leaving the baseline has nothing to do with it. Neither does "backing away" from 1B (that is, taking a step backward). Those apply only when the batter-runner is avoiding or delaying a tag.

Re: Memory don't fail me now...
 

True, but only when the batter-runner is attempting to avoid or delay a tag. No tag is possible on a walk, so this rule does not apply.

See my answer above. The runner is not out for giving up or for abandoning this attempt to advance - ASA does not have that rule. He would have been out, though, for entering the bench area (fast pitch). The ASA rule is virtually the same as the FED rule you quoted.

Fast Pitch- Batter/runner-OUT, Slow Pitch-Wake him up, then put him on first.