In case you didn't know, whenever you post the exact same answer as was already posted, it gets converted to a comment.
I had no idea before I posted a crack on a cops-and-robbers post that someone had posted 5s before.
I didn't know what happened before someone asked me why I commented on the question. I was confused for a bit until I figured it out.
While this may make sense for a Q&A site, it doesn't make sense for PPCG. 99% of the time, 2 people had the same idea at the same time.
Here's what I'm proposing:
When you post a duplicate answer, this message appears:
Your answer is an exact duplicate of another answer. Please edit your answer if you would like to post it.
If this gets enough votes, I will post this to mother meta.