Document preset test continuity plan

docs/preset_test.md

@@ -41,6 +41,15 @@ required.
       </dl>
     </section>
 
+    <section class="preset-test-warning" aria-labelledby="continuity-plan-title">
+      <h2 id="continuity-plan-title">Bridges and early-revert plan</h2>
+      <p>
+        The test will include bridges. If the Puget Sound area experiences a
+        widespread power outage or loss of cellular service, we will end the
+        test early and revert to the normal 910.525 MHz channel.
+      </p>
+    </section>
+
     <section class="preset-test-warning" aria-labelledby="save-settings-title">
       <h2 id="save-settings-title">Before changing a radio</h2>
       <p>