Locked threads have tiny lock icon and a thin line of locked thread notice above and below the thread. For normal members the quick reply editor is not shown below locked thread but it does appear for staff members. Indeed this is how it should be. But we encounter many such occasions when a staff member has locked a thread and some other staff member has posted reply in the same thread without noticing that the thread was actually locked. Replies from staff member in locked threads should ideally be some sort of notice, warning, announcement or request. But if unintentionally a staff member posts a reply that pushes the discussion forward, members start complaining that staff is misusing their power by posting their views on topic and not allowing others to do so.