Sitecore Authentication on CES Discovery service failed

Any good Sitecore developer periodically checks their production logs for any error messages or worrying warnings. Whilst doing this on an 8.2 implementation, I noticed the following warning:

ManagedPoolThread #3 09:15:45 WARN Authentication on CES Discovery service failed.
Exception: System.Net.WebException
Message: The remote server returned an error: (403) Forbidden.
Source: System
at System.Net.HttpWebRequest.GetResponse()
at Sitecore.CES.Client.WebClient.ExecuteRequest(String requestUri)
at Sitecore.CES.Client.ResourceConnector`1.Request(String endpoint, Object[] parameters)
at Sitecore.CES.Discovery.EndpointSource.GetEndpoint(String serviceName)

The line before this in the logs states:

INFO  Job started: Update device detection DB

Which  traces back to device detection in Sitecore which is a paid service (since Sitecore 8.1). This can be disabled by using the following patch file:

<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <settings>
      <setting name="DeviceDetection.Enabled">
        <patch:attribute name="value">false</patch:attribute>
      </setting>
    </settings>
  </sitecore>
</configuration>

It will then begin to insert the following (more graceful) warning :)

WARN  Device detection component is disabled

For those users who want to use this service, remember to enable the connections to discovery-ces.cloud.sitecore.net and devicedetection-ces.cloud.sitecore.net on the firewall.