During a support issue with one of my clients, I noticed a unexpected result when using filtered views which allows access to data without consuming a user license.
It would appear that when a user is put in restricted access mode (access to settings but no data) in Microsoft CRM 3.0 the user is not restricted access to data made available through the Filtered Views, yet the user's security roles are still considered and data is filtered accordingly.
I'm yet to see whether this still is the case using the Web Services, but it would appear that only the application checks to see if the user is in RMA.
If this is the case, expect it to be plugged.