Yosemite has been enjoying record post-card moments with all its waterfalls gushing more than most people can ever remember seeing. The water table is at a 5-decades peak, too.
Look at the video below, and see how close to the guard-rail area the water is actually gushing, and then consider that someone crossed the railing and waded into the water about 25 feet from the Vernal waterfall there yesterday. Two would-be rescuers went in, too, and all three went over the edge. I don't think you'd have to be a rocket-surgeon to surmise that getting your feet wet here is not a good idea.
I know people aren't very smart, but sometimes it's really disappointing how not-smart they are.