I don't think this should ever be done. A better way to address the presumed problem (and something that would be useful for many other reasons) is to make available the consideration history of a node including when it was considered, for what, how the vote turned out, when and why it was unconsidered (which will require asking for a reason when janitors unconsider a node), etc. Perhaps considering a node that had previously been considered could display the consideration history and prompt "are you sure?". Fixing a title once doesn't mean that a much better title can't be suggested. Not being a duplicate once doesn't mean it can't become a duplicate. Or a poorly worded consideration might fail for the wrong reasons. Etc.