In case you're new and would like to become a host, the concept of "consensus" is bound to arise!
Hosts have discussed this, and admins have replied to the question. Here:
It need not be unanimous. But there must be the consensus. I tend to think that if one person is strongly opposed to a lock, and is making that stand based on some principle they are able to articulate, then that position should be respected and consensus does not exist. But if some people are just-kinda-meh-not-sure opposed to a lock, then you can assume that consensus exists. But I think the bigger picture is that if everyone is doing the job in good faith and being polite to each other, then it should not be very hard to determine if consensus exists and act accordingly.
http://www.democraticunderground.com/12595617 ~~~~~~
My emphasis is here:
I tend to think that if one person is strongly opposed to a lock, and is making that stand based on
some principle they are able to articulate, then that position should be respected and consensus does not exist.