I've not received any requests, though JD Worthington I believe did, but he's not able to moderate in the aspiring writers section anyway.
As for the overall requests - the edit function ceases to work after around 15-20 minutes. It gives enough time to correct typos, while also allowing posts to remain constant enough to be replied to.
The edit function needs a cut off, because I've seen people elsewhere abuse this function to rewrite posts in order to change the meaning of entire threads, usually to disadvantage other members.
As Culwich points out, the issue of covering removal of material is covered in the Terms of Use and in the announcement on the Critiques board.
The reason is simple.
The staff here are all volunteers, and if the removal process were left unchecked, I assure you we would have people everyday asking for material to be removed, and expecting chronicles staff to do this for them, which simply isn't fair on the staff.
Therefore we try and encourage people to be responsible with how they post in the first place.
If anyone's worried about potential plagiarism issues - firstly, it's extraordinarily difficult to come up with new concepts that haven't already been published in fiction in already. Secondly, it's extraordinarily difficult to become a traditional published writer, and different writers will always treat the same subject matter differently.
So overall, I really don't think people have to worry about outright plagiarism, because I think the reality is that it's unlikely to happen here.
Of course, no one should be posting full works on chronicles unless they accept that others may repost it without authorisation - but again, that's why we try to encourage responsible posting by asking that only excerpts be posted - which is usually more than sufficient for any feedback and critique.
Hope that helps.