Authorization plugin: unsetting roles?

Hi there

I'm using the Authorization plugin but am having trouble unsetting
roles.

I'm off and running with it using it on top of acts_as_authenticated
but am having trouble unsetting roles once I've set them.

A Survey has_many :users, :dependent => :delete_all and is
acts_as_authorizable

A User belongs_to :survey and is acts_as_authorized_user and
acts_as_authorizable

In the console, this is what I am playing with:

<pre>

s = Survey.new

=> #<Survey...

u = User.new

=> #<User...

u.is_target_of s

=> [#<Role...]

s.has_targets?

=> true

s.has_targets.size

=> 1

s.has_targets[0].id

=> 2

u.id

=> 2 # so survey target is set properly

# Now to unset the role

u.is_not_target_of s

=> nil

u.has_no_role 'target', s

=> nil

# target still exists!

s.has_targets.size

=> 1

So I'm confused why I can set the 'target' role for @survey but can't
unset the same way?

Any clues would be appreciated.