[exim] ACL error bypass?

Is there a way to tell an ACL to just bypass and do nothing in the case
where it normally would return a "Tempory Local Problem" because of
something like a failed string expansion or a missing file?

The problem I'm trying to fix is that I'm allowing users to type in
strings to block messages in headers. But if the user types something
that "match" doesn't like then they end up getting their email blocked
and no knowing what happened. I'd like to have an "ignore errors"
command in an ACL so that if there's some kind of failure the ACL is
silently bypassed.