Several times now I've done something like:

$ git annex unlock movie.avi
$ mv /tmp/fixed.avi movie.avi
$ git annex lock movie.avi

Oops, I just lost my fixed.avi! That really feels like the right sequence of operations to me, so I'm always surprised when I make that mistake. I would like to see the current lock renamed to something like undo-unlock, or have the behavior changed to be the same as add, or maybe warn and require a --force when the file has been changed.

If changing current behavior is undesirable, maybe unlock could just print a reminder that git annex add is the correct next step after making changes?

Failing that, I suppose I could slowly start to learn from my mistakes.