I often use views as part of a data review process, where users can flag records as "reviewed" or "rejected" by setting an attribute value. I typically give them access to that field along with a text field for review notes, while disabling adds, deletes, geometry updates, and updates to all other attributes. I'd like them to be able to view attachments but as data reviewers they shouldn't be allowed to add new attachments or delete existing attachments, and I don't believe that's currently possible. The best workaround I can come up with is to hide attachments on the editable view, while exposing a second read-only view with attachments visible (kind of clunky).
It would also be great to have views configured so that users could add new attachments, but block them from deleting existing attachments. I believe this can be controlled in S123 forms but it would be preferable if it was enforced at the service level.