diff --git a/.spectral.yml b/.spectral.yml
index 08324ead..e60e7861 100644
--- a/.spectral.yml
+++ b/.spectral.yml
@@ -2,7 +2,6 @@ extends: [["spectral:oas", "all"]]
 formats: ["oas3"]
 rules:
   operation-singular-tag: off
-  operation-default-response: off
   oas3-parameter-description: off
   contact-properties: off
   operation-tags: error
diff --git a/apis/eventstream/index.yaml b/apis/eventstream/index.yaml
index d9f7ba45..b0b0f748 100644
--- a/apis/eventstream/index.yaml
+++ b/apis/eventstream/index.yaml
@@ -8,6 +8,9 @@ get:
     Provides endpoint to subscribe to beacon node Server-Sent-Events stream.
     Consumers should use [eventsource](https://html.spec.whatwg.org/multipage/server-sent-events.html#the-eventsource-interface)
     implementation to listen on those events.
+
+    Servers _may_ send SSE comments beginning with `:` for any purpose, including to keep the
+    event stream connection alive in the presence of proxy servers.
   parameters:
     - name: topics
       in: query