Are users obligated to read (or at least skim) existing answers before posting a new answer?
I can see one reason for "yes": it would reduce redundant answers. But How to write a good answer doesn't mention any such obligation.
There's another Help Center article, Why and how are some answers deleted?:
Answer posts that do not fundamentally answer the question may be removed. This includes answers that are:
- exact duplicates of other answers
This is a bit contradictory; of course the duplicate answer does answer the question. And an answer does not need to be an exact duplicate, just like a question doesn't have to be an exact duplicate to be closed as such.
Since it's a waste of time to write answers which are later deleted, we can conclude users should read other answers before posting.
Well, because nothing tells us we have to read it, we don't have to.
But whether or not you read it, we (or at least some of us) can close your answer if your answer doesn't add anything extra (that is useful) to the question.
If you decide, though, that you just want to try to get suspended or lose reputation on purpose, that's a good way.
Common sense tells us that users should at least skim existing answers to avoid duplication.
Generally, you should read the other answers, but you wouldn't be punished solely for not reading the other answers, only if this causes you to post duplicate answers.