You don't get my point. Here's my point:

So I ask again, how do we educate the community on the nuance of wording?

You don't. You can't.

You can't just expect everybody else to change their behavior. That's ridiculous. Unless you actually make everyone on Reddit a box except for you, it's not going to happen.

Let's take a look at your example:

Birthday clowns, what have been your most heartwrenching experiences?

Let's imagine I want to make this open to any serious answer. Here are the two scenarios:

1. I have a choice between First-Hand Accounts Only and Serious Answers Only: I click on "Serious Answers Only" and ask my questions.

2. I can only choose First-Hand Accounts Only. I try to think of a way to type it that's an open as possible. Maybe I say "Clowns, people who have been in the presence of clowns, and people who have heard clown-related stories: What was the most heart-wrenching experience you were a part of, witnessed, heard described or learned about in another way?"

I can't even say, "What's your more heart-wrenching clown-related experience", because that's still limited to first-hand answers. I can't say "What birthday clown-related stories do you know that will have an emotional impact", because now I've opened it up to fictional accounts.

You keep talking about "OP's request", but you've made it a linguistic minefield to make the request you want.

Beyond that, people upvote sensational titles. Carefully worded titles are just going to die anyway.

The First-Hand Tag makes it way, way easier.

Now, you also said this:

... without giving the team more work on top of it?

I don't understand this. The First-Hand Tag would give you way less work.

Right now, you delete popular threads with the Serious tag purely because the odds of getting a First-Hand Account are low. You also have to waste so many hours browsing every Serious question for any second-hand account that you actually have a special mod team just dedicated to the tag.

With the addition of the First-Hand tag, you'd have less heavy moderation-requiring threads to browse through and you'd have less work.

Again, the bottom-line is this:

You need to make the experience easier on the user and stop expecting the user to do what you want.