When a question is a duplicate, or on hold, you can see a sign, e.g. [on hold]
, next to the title in the list of questions, so that you don't waste your time clicking on it unless you really want to.
When it is locked, however - which happens a lot due to the ongoing contest politics - I don't see a [locked] sign. It would be appropriate given that there is really no way to interact with a locked question, you can't even upvote comments.
Edit: one possible workaround would be to actually put such questions on hold - possibly on top of locking them. Yet you can't even vote to close a question that was locked, so it has to be done before or by a moderator.
I'm coming back to this because of this question: I'd long been thinking about it when I found out that it was locked.