Security in TM1 10.1

[Elessar]

Hi,
I have a question about the new security 10.1:

Assume the user has the 'VIEW' access to all nodes of an application in Contributor. And there is a cube in the application with a rule "[] = S: 'WRITE'" in it's }CellSecurity_ cube.
In 9.5.2 the user will be able to edit data in this cube, because }CellSecurity_ is stronger that }ElementSecurity_(approval Hierarchy dimension)
But in 10.1 the user cannot edit the cube, because the new Contributor security is stronger. Can I do something in rules/TI to let user edit the cube despite the Contributor's 'READ'?

P.S. I will be wery happy, if someone explains me (or gives a link to some document), what's happening, when a user takes the ownership in 10.1. In 9.5.2 the user is added to the }tp_owner group, but there are no such groups in 10.1.

Thanks for advance

[PlanningDev]

If im not mistaken starting with 10.1 contributor uses Data Reservation to control contributor security access. A user who takes ownership of a node is given a data reservation which essentially locks out all other users untill this reservation is released. A data reservation is released when another user takes ownership or possibly if a you manually run a TI to release the data reservation for that user. Not sure if that would mess up contributor or not however.