diff --git a/consul/session_endpoint.go b/consul/session_endpoint.go
index f7e46636f4..cfe60ea570 100644
--- a/consul/session_endpoint.go
+++ b/consul/session_endpoint.go
@@ -31,9 +31,10 @@ func (s *Session) Apply(args *structs.SessionRequest, reply *string) error {
 	switch args.Session.Behavior {
 	case structs.SessionKeysRelease, structs.SessionKeysDelete:
 		// we like it, use it
-
-	default:
+	case "":
 		args.Session.Behavior = structs.SessionKeysRelease // force default behavior
+	default:
+		return fmt.Errorf("Invalid Behavior setting '%s'", args.Session.Behavior)
 	}
 
 	// If this is a create, we must generate the Session ID. This must
diff --git a/consul/state_store.go b/consul/state_store.go
index 2bd0396ef4..0173cff697 100644
--- a/consul/state_store.go
+++ b/consul/state_store.go
@@ -1330,9 +1330,10 @@ func (s *StateStore) SessionCreate(index uint64, session *structs.Session) error
 	switch session.Behavior {
 	case structs.SessionKeysRelease, structs.SessionKeysDelete:
 		// we like
+	case "":
+		session.Behavior = structs.SessionKeysRelease // force default behavior
 	default:
-		// force SessionKeysRelease
-		session.Behavior = structs.SessionKeysRelease
+		return fmt.Errorf("Invalid Session Behavior setting '%s'", session.Behavior)
 	}
 
 	// Assign the create index