Checking desired seems like it's predicated on https://github.com/rackerlabs/otter/pull/618 landing - which I think it will and is what we want anyway, but I don't know if we've checked with reach yet.  Just wanted to leave a note here in case something goes wrong with that change.

It just might be confusing for the user currently (since that change has not been made) because they might see that desired is at min (because it's active and pending), and deleting a server may let them go successfully below min (if we failed to spin up a bunch of servers, and the stored desired is actually higher than what the user currently sees).