Doesn't bother me, but it does seem to bother the people who come up with these lists. (I am slightly bothered, though, by people who click on a a link, and then click it again when it's "loading too slowly," thinking that they're hurrying it along instead of going back to the start of a new request.) The best solution in both cases would be for the browser to simply ignore any attempts to load a GET of URL X in a given frame/window/tab when it's already attempting to load the same GET of URL X in that frame/window/tab.