That is correct, you can add, but you cannot remove or modify existing data.
We do have a limited template front-end hook system (yet to be blogged) but that again does not have a replace option.
Excellent
This prevents conflicts between 3rd-party apps. Currently, if there is an app that removes or replaces attributes and another app wants to work by using these attributes, it is not possible. I had encountered this problem.
IC5: UI Extensions, Part I
in Blog
Posted
Excellent
This prevents conflicts between 3rd-party apps. Currently, if there is an app that removes or replaces attributes and another app wants to work by using these attributes, it is not possible. I had encountered this problem.