Docs: Add users being removed if no SAML group

doc/user/group/saml_sso/index.md

@@ -362,6 +362,11 @@ the user gets the highest access level from the groups. For example, if one grou
 is linked as `Guest` and another `Maintainer`, a user in both groups gets `Maintainer`
 access.
 
+Users who are not members of any mapped SAML groups are removed from the GitLab group. 
+
+You can prevent accidental member removal. For example, if you have a SAML group link for `Owner` level access
+in a top-level group, you should also set up a group link for all other members.
+
 ## Glossary
 
 | Term | Description |