diff --git a/draft-ietf-moq-transport.md b/draft-ietf-moq-transport.md
index e02bbc22..9c07ffbf 100644
--- a/draft-ietf-moq-transport.md
+++ b/draft-ietf-moq-transport.md
@@ -2182,6 +2182,10 @@ OBJECT_DATAGRAM Message {
 ~~~
 {: #object-datagram-format title="MOQT OBJECT_DATAGRAM Message"}
 
+If an endpoint receives an OBJECT_DATAGRAM with a Track Alias that does not
+correspond to an active or recently closed subscription, it closes the session
+with a protocol violation.
+
 ## Streams
 
 When objects are sent on streams, the stream begins with a stream header
@@ -2222,6 +2226,11 @@ following fields.
 
 The Object Status field is only sent if the Object Payload Length is zero.
 
+If an endpoint receives a STREAM_HEADER_SUBGROUP with a Track Alias that does
+not correspond to an active or recently closed subscription, it closes the
+session with a protocol violation.
+
+
 ~~~
 {
   Object ID (i),
@@ -2318,6 +2327,9 @@ FETCH_HEADER Message {
 ~~~
 {: #fetch-header-format title="MOQT FETCH_HEADER Message"}
 
+If an endpoint receives a FETCH_HEADER that references a subscription ID that does
+not refer to an active or recently closed FETCH, it closes the connection with a
+Protocol Violation.
 
 Each object sent on a fetch stream after the FETCH_HEADER has the following format: