diff --git a/src/LaunchDarkly/LDClient.php b/src/LaunchDarkly/LDClient.php
index 7c8261ab9..fb1005b31 100644
--- a/src/LaunchDarkly/LDClient.php
+++ b/src/LaunchDarkly/LDClient.php
@@ -111,11 +111,14 @@ public function variation($key, $user, $default = false) {
         }
 
         try {
-            if (is_null($user) || strlen($user->getKey()) === 0) {
+            if (is_null($user) || is_null($user->getKey()) ) {
                 $this->_sendFlagRequestEvent($key, $user, $default, $default);
-                $this->_logger->warn("Variation called with null user or null/empty user key! Returning default value");
+                $this->_logger->warn("Variation called with null user or null user key! Returning default value");
                 return $default;
             }
+            if (strlen($user->getKey()) === 0) {
+                $this->_logger->warn("User key is blank. Flag evaluation will proceed, but the user will not be stored in LaunchDarkly.");
+            }
             $flag = $this->_featureRequester->get($key);
 
             if (is_null($flag)) {