If you check the [docs](https://developers.google.com/analytics/devguides/collection/analyticsjs/events#implementation) the output should be omitting the variables. Afaik it's just like you did with transactions and transaction items.

So `$params = array(/* ... */);` and then:

```
if ($event->getLabel()) {
  $params[] = $event->getLabel();
}

if ($event->getLabel() && $event->getValue()) {
  $params[] = $event->getValue();
}
```

Or do I misunderstand the docs here?