Way back in Tip 226, we talked about the sitemap privilege tag that can be used to hide sitemap subarea links for users that don’t have a specific entity permission. One thing that you should know is that the privilege tag is not honored by Dynamics CRM mobile apps.
The rule of thumb is that if a user has permission to read an entity, the entity is enabled for mobile, and a link to that entity is displayed in the sitemap, the user will see that entity listed in the menu of CRM mobile apps.
As a practical consequence, if your users use CRM mobile apps on their smartphones or tablets, you may want to avoid putting every back-end custom entity in the settings area of the sitemap. For entities that are used for purposes like lookup lists, you want the entity to be available on mobile, but you probably don’t want the link to appear in the menu of the mobile apps. My recommendation is to not display the entity in the settings menu. Users who need to add records to these entities or manage the records in them can do so by running an Advanced Find query.