Right, that is filtering by user properties.
Some segments, including browser, are set on session start only. And the rest of requests won't contain that information anymore. So to be able to block all the rest of requests, we need to create relation, that for this device_id browser is this. And thus need to create the document. But the data should not be counting for those users.
I think better would be to block them on SDK side:
I will add PingdomBot and some others new I have seen in SDK