If a user has access to collaboration module, he may open /collaboration/item/full of any object pending approval, even if he is not an approver for that specific object. The Approve and Deny buttons, although not working, will still be visible, which may lead to some confusion (If the user clicks any of these buttons, nothing will happen in the backend, but no message will be displayed either).

Suggestion of an improvement is to remove or disable these buttons when the current user cannot approve the previewed object.