Document that baggage is sent to external APIs by automatic instrumen…

…tation

content/en/docs/concepts/signals/baggage.md

@@ -34,7 +34,7 @@ retrieve information.
 
 OTel Baggage should be used for data that you're okay with potentially exposing
 to anyone who inspects your network traffic. This is because it's stored in HTTP
-headers alongside the current context. If your relevant network traffic is
+headers alongside the current context, and may be sent to external APIs by automatic instrumentation. If your relevant network traffic is
 entirely within your own network, then this caveat may not apply.
 
 Common use cases include information that’s only accessible further up a stack.