I've seen a couple of instances where changes to MediaWiki are blocked until someone informs the community.
Someone is a volunteer.
Community is actually just the Wikimedia project communities. Or at least the biggest ones which are expected to complain and where the complaining would hurt.
This situation seems completely unfair to me. WMF should be able to communicate upcoming changes itself, not throw it to volunteers. Volunteers can help, but they should not be responsible for this to happen.
-Niklas