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But, also users don't lock their own thread now. I don't think they would care for automatically expiring their thread.
I think the best solution would be to set a default time of expiry for every thread created. OP would still have the option to re-open the thread if needed, otherwise it should remain closed.
If we were to talk about expiry times, I think 1 week would be good enough.
Going back to reality, although this is a good idea/feature, I don't think this will be implemented (if ever)
