diff --git a/src/main.cpp b/src/main.cpp
index dcf2dd1..b117199 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -282,15 +282,30 @@ int main(int argc, char** argv) {
         net.stop();
         net.print_diagnostics();
 
+        /// TRACES: AR-004 | SR-002
+        // A dropped frame does not degrade a result, it silently changes one —
+        // the output is a claim about footage that was never analysed, and
+        // nothing in the file says so. Since AR-004 made data pushes block, a
+        // drop can no longer happen on the data path, so any drop here means
+        // either that fix regressed (it lives in the KPN submodule, one line,
+        // easy to lose in an update) or a channel was disabled mid-run.
+        //
+        // Reporting it in a footer and exiting 0 made both invisible: the run
+        // "succeeded" and the truth file looked complete. Fail instead.
+        bool dropped = false;
         {
             std::lock_guard<std::mutex> lk(event_mtx);
             if (!overflow_counts.empty()) {
-                std::cerr << "[main] dropped frames (channel overflow):\n";
+                dropped = true;
+                std::cerr << "[main] ERROR: frames were dropped (channel overflow):\n";
                 for (const auto& [name, count] : overflow_counts)
                     std::cerr << "  " << name << ": " << count << "\n";
+                std::cerr << "[main] The output would describe footage that was never "
+                             "analysed. Refusing to report success.\n";
             }
         }
-        return node_crashed.load(std::memory_order_acquire) ? 1 : 0;
+        if (node_crashed.load(std::memory_order_acquire)) return 1;
+        return dropped ? 2 : 0;
     };
 
     // ── Build static network and run ──────────────────────────────────────────