Ability to remove self from someone else's organization/collection

If you’re seeing all their collections in clients other than the Web Vault - you can change that setting for your user. In the Web Vault under Manage > People, click on your user and change it to “This user can access only the selected collections”

You’ll only see the assigned collections in all your clients, and if you need to see anything in a “private” collection, you would do so in the Web Vault, after switching to the Organization view.