To reiterate, setting the annotation to any value which does not match a valid ingress class will force the NGINX Ingress controller to ignore your Ingress.
If you are only running a single NGINX ingress controller, this can be achieved by setting the annotation to any value except "nginx" or an empty string.
This mechanism also provides users the ability to run _multiple_ NGINX ingress controllers (e.g. one which serves public traffic, one which serves "internal" traffic).
To do this, the option `--ingress-class` must be changed to a value unique for the cluster within the definition of the replication controller.