I've got to wonder: Is a pirate likely to actually try to have a fair fight?
Scurvy sounds more like an Intimidate (or a Truant effect because it's just that non-specific) ability more than an equalizer.
Ruthless sounds better than the other two, in my opinion, it just doesn't really convey the ability's effect (anybody else reminded of Reckless).
I'm almost tempted to back simple Unaware (c wat i did thar?) because of its accessibility - we already have enough people asking what Mountaineer does.
EDIT: If we do something other than Unaware, though. Avast sounds bitchin'. :D