Prevent message echo on native crdt

src/intelligence-exfiltrator.js

@@ -39,7 +39,10 @@ export default class Exfiltrator {
       return
     }
 
-    if (disableSend) {
+    const existingMapping = XCDPIdentifierFrom(id)
+    if (disableSend || (existingMapping && existingMapping !== id)) {
+      // Prevent echoing secret intelligence back to the room
+      // disableSend for Yjs, reverse-lookup for XCDPId == OurId for Native
       return
     }
 
@@ -199,8 +202,6 @@ const XCDPIdentifierFrom = (lineID) => {
       return XCDPID
     }
   }
-
-  throw new Error("XCDP identifier unexpectedly not present")
 }
 
 function parseColourComponent(component) {