diff --git a/cmd/gazctl/gazctlcmd/shards_prune.go b/cmd/gazctl/gazctlcmd/shards_prune.go
index e30ba10a..fc7f7a96 100644
--- a/cmd/gazctl/gazctlcmd/shards_prune.go
+++ b/cmd/gazctl/gazctlcmd/shards_prune.go
@@ -152,11 +152,8 @@ func foldHintsIntoSegments(hints recoverylog.FSMHints, sets map[pb.Journal]recov
 	for _, segment := range segments {
 		var set = sets[segment.Log]
 
-		// set.Add() will return an error if we attempt to add a segment having a
-		// greater SeqNo and LastOffset != 0, to a set already having a lesser
-		// SeqNo and LastOffset == 0. Or, if FirstSeqNo is equal, it will replace
-		// a zero LastOffset with a non-zero one (which is not what we want
-		// in this case).
+		// If FirstSeqNo is equal, set.Add will replace a zero LastOffset with a
+		// non-zero one (which is not what we want in this case).
 		//
 		// So, zero LastOffset here if |segment| isn't strictly less than
 		// and non-overlapping with a pre-existing last LastOffset==0 element.
diff --git a/consumer/recoverylog/segment.go b/consumer/recoverylog/segment.go
index 56f76c64..9d0d85f4 100644
--- a/consumer/recoverylog/segment.go
+++ b/consumer/recoverylog/segment.go
@@ -141,8 +141,6 @@ func reduceSegment(a, b Segment) (Segment, error) {
 	// Offset ordering constraint checks.
 	case a.FirstSeqNo < b.FirstSeqNo && a.Log == b.Log && a.FirstOffset > b.FirstOffset:
 		return a, fmt.Errorf("expected monotonic FirstOffset: %#v vs %#v", a, b)
-	case a.FirstSeqNo < b.FirstSeqNo && a.LastOffset == 0 && b.LastOffset != 0:
-		return a, fmt.Errorf("expected preceding Segment to also include LastOffset: %#v vs %#v", a, b)
 
 	case a.LastOffset == 0 && a.Log != b.Log:
 		// This cases isn't strictly required, but it's true of the intended
diff --git a/consumer/recoverylog/segment_test.go b/consumer/recoverylog/segment_test.go
index 09f5c00e..a4771d87 100644
--- a/consumer/recoverylog/segment_test.go
+++ b/consumer/recoverylog/segment_test.go
@@ -76,9 +76,9 @@ func (s *SegmentSuite) TestSegmentReductionCases(c *gc.C) {
 		},
 		// Overlap, and preceding Segment is missing LastOffset.
 		{
-			a:   Segment{Author: 0x1, FirstSeqNo: 2, LastSeqNo: 7, FirstOffset: 200, LastOffset: 000, FirstChecksum: 0x22, Log: A},
-			b:   Segment{Author: 0x1, FirstSeqNo: 4, LastSeqNo: 9, FirstOffset: 400, LastOffset: 901, FirstChecksum: 0x44, Log: A},
-			err: "expected preceding Segment to also include LastOffset: .*",
+			a: Segment{Author: 0x1, FirstSeqNo: 2, LastSeqNo: 7, FirstOffset: 200, LastOffset: 000, FirstChecksum: 0x22, Log: A},
+			b: Segment{Author: 0x1, FirstSeqNo: 4, LastSeqNo: 9, FirstOffset: 400, LastOffset: 901, FirstChecksum: 0x44, Log: A},
+			e: Segment{Author: 0x1, FirstSeqNo: 2, LastSeqNo: 9, FirstOffset: 200, LastOffset: 901, FirstChecksum: 0x22, Log: A},
 		},
 		// Overlap, mismatched authors.
 		{
@@ -98,6 +98,12 @@ func (s *SegmentSuite) TestSegmentReductionCases(c *gc.C) {
 			b: Segment{Author: 0x1, FirstSeqNo: 3, LastSeqNo: 6, FirstOffset: 300, LastOffset: 000, FirstChecksum: 0x33, Log: A},
 			e: Segment{Author: 0x1, FirstSeqNo: 2, LastSeqNo: 7, FirstOffset: 200, LastOffset: 701, FirstChecksum: 0x22, Log: A},
 		},
+		// Covered, with 0 LastOffset
+		{
+			a: Segment{Author: 0x1, FirstSeqNo: 2, LastSeqNo: 7, FirstOffset: 200, LastOffset: 701, FirstChecksum: 0x22, Log: A},
+			b: Segment{Author: 0x1, FirstSeqNo: 1, LastSeqNo: 8, FirstOffset: 2, LastOffset: 0, FirstChecksum: 0x33, Log: A},
+			e: Segment{Author: 0x1, FirstSeqNo: 1, LastSeqNo: 8, FirstOffset: 2, LastOffset: 0, FirstChecksum: 0x33, Log: A},
+		},
 		// Disjoint.
 		{
 			a:   Segment{Author: 0x1, FirstSeqNo: 2, LastSeqNo: 4, FirstOffset: 200, LastOffset: 401, FirstChecksum: 0x22, Log: A},
@@ -122,6 +128,12 @@ func (s *SegmentSuite) TestSegmentReductionCases(c *gc.C) {
 			b: Segment{Author: 0x1, FirstSeqNo: 2, LastSeqNo: 9, FirstOffset: 210, LastOffset: 901, FirstChecksum: 0x22, Log: A},
 			e: Segment{Author: 0x1, FirstSeqNo: 2, LastSeqNo: 9, FirstOffset: 210, LastOffset: 901, FirstChecksum: 0x22, Log: A},
 		},
+		// Equal-left, with LastOffset: 0
+		{
+			a: Segment{Author: 0x1, FirstSeqNo: 2, LastSeqNo: 7, FirstOffset: 200, LastOffset: 701, FirstChecksum: 0x22, Log: A},
+			b: Segment{Author: 0x1, FirstSeqNo: 2, LastSeqNo: 9, FirstOffset: 200, LastOffset: 000, FirstChecksum: 0x22, Log: A},
+			e: Segment{Author: 0x1, FirstSeqNo: 2, LastSeqNo: 9, FirstOffset: 200, LastOffset: 000, FirstChecksum: 0x22, Log: A},
+		},
 		// Equal-left, but checksum mismatch.
 		{
 			a:   Segment{Author: 0x1, FirstSeqNo: 2, LastSeqNo: 7, FirstOffset: 200, LastOffset: 701, FirstChecksum: 0x22, Log: A},
@@ -254,9 +266,6 @@ func (s *SegmentSuite) TestSetConsistencyChecks(c *gc.C) {
 		// Overlapping, incorrect log.
 		{Segment{Author: 0xa, FirstSeqNo: 4, LastSeqNo: 5, FirstOffset: 400, LastOffset: 501, Log: "wrong"},
 			"expected Segment Log equality: .*"},
-		// Missing LastOffset.
-		{Segment{Author: 0xb, FirstSeqNo: 12, LastSeqNo: 12, FirstOffset: 1200, LastOffset: 000, Log: A},
-			"expected preceding Segment to also include LastOffset: .*"},
 		// Non-monotonic offsets.
 		{Segment{Author: 0xb, FirstSeqNo: 12, LastSeqNo: 12, FirstOffset: 1050, LastOffset: 1200, Log: A},
 			"expected monotonic FirstOffset: .*"},