Validator milk example, success fire on selected inputs

Validator milk example, success fire on selected inputs

I am playing around with the milk example in the Validator plugin and would like the success event (that puts the tick in place) to fire only for selected inputs. I want to adapt the form for a login form, but putting a tick next to a username may imply that the user has entered a correct username, not simply one that conforms to the requirements (ie length).

Is there a way to stop the success event firing for certain fields, or can I somehow adapt the DOM to stop the tick showing, but still allowing room for the error message if required?

Thanks in advance.