[Zope] Local Roles - taking away further down the tree?

[Etienne Labuschagne]

Hi there,

First, AFAIK local roles are acquired further down the tree - if I assign a 
local role, the user will have that local role in that folder's children too.

Is is possible to "remove" the local role of a user in a folder/set of 
folders further down the tree?

If this is not possible and maybe even a stupid idea, please fire away - I 
need some ammo to convince the client that this is anyway not a good idea - 
even if it cannot be done!

Thanks
Etienne