I've recently noticed an increased incidence of questioners repeating their question if no reply (or one they can accept) is received toot suite or in a time scale of their choosing.
Often, they will delete their first attempted question before reposting or when the dupe is noted in comments, they will then delete the first incidence.
In one recent case, the question was answered but since the questioner seemingly didn't agree with the answer given, the question was again repeated.
Is there a policy on how best to handle this? Some questioners have become quite aggressive when challenged.