Hmm.. he must get a notification everytime he's tagged (or quoted), so I think there would be no need to "bump" the request.
Anyways, koko is a saint... He should receive a medal or something for putting up with all these constant demands. I do feel people could try to meet him halfway, and in the process minimize the endless repeated requests. As suri has pointed out, a lot of the times people keep asking for videos that are no longer available. And some people even send him links for websites he can't download off (such as recurbate). So they could do some of the work themselves and previously check if the video is actually available, or at least in the right website where he can download (camvideos).