Hi David,
First of all I am not in favor of "misusing" authorization to hide one or more attributes. This can have a negative impact on performance and is in my opinion not transparent.
The other option of deleting attributes which are not used is a better approach.It will certainly pay-off to make multi-dimensional data models leaner. Especially with Business Content there are often too many attributes which are never going to be used.
Last but not least, please have a look at my blog Generating Reporting InfoObjects based on Business Content - Part 1: Introduction for an alternative approach.
Best regards,
Sander
