This question is a follow up of How was this answer posted after this question was closed?, which explains how it is possible that an answer is posted hours after it was closed or put on hold.
The current system doesn't really prevent answering bad questions, since the block on posting answers on recently closed questions is just client-side (an in-browser HTML change will do circumvent this).
I think this is bad, especially on sites suffering from bad questions, like SO, but possibly a lot more sites.
I would propose to make this block more strict to prevent answering bad questions.
- Prevent answering at all server-side (so if you started typing an answer, your answer will be 'lost' until the question is reopened);
- Auto-flag users that frequently answer closed questions (they might be the users tricking the system);
- Any other suggestion from your side to make this better.