Add privacy protection to MerchantValidationEvent's validationURL (#850)

Author: marcoscaceres

index.html

@@ -5337,6 +5337,15 @@ <h2>
         </p>
       </section>
       <section class="informative">
+        <h2>
+          Merchant Validation
+        </h2>
+        <p data-link-for="MerchantValidationEvent">
+	  It is important that the <a>validationURL</a> in a
+	  <a>MerchantValidationEvent</a> does not expose personally
+	  identifying information to unauthorized parties.        
+	</p>
+      </section>
         <h2 id="canmakepayment-protections">
           <code>canMakePayment()</code> protections
         </h2>