Difference in removing all / single subscriber

I was looking at the `removeSubscriber` method of the `Channel` object and I noticed something that I can't explain.

When removing a specific subscriber you set the `channel` property of the subscriber to `null` before removing it from the array of subscribers. When all the subscribers get cleared due to the `id` param being `null` the array is simply cleared and the `channel` property on all the subscribers don't get reset to `null`.

Is there a specific reason for this or is it an oversight?