If a user is added to a project, when they next sync their device they are now able to access the records within that project (in apps they have access to). But when they are later removed from the project, the records remain locally on their device until they delete them, or reset the records cache.
It would be useful if when a user is removed from a project, the synced records are automatically removed from their device when they next sync.
This would help keep things clean for the user but also prevent the user storing potentially sensitive data longer than necessary.