I teach 2nd grade.
Within the first 2 days of school, three of my students had legitimate bloody noses. Unfortunately, this seems to have started a trend. Now, my students have developed the habit of randomly getting up, running to the kleenex box, yanking out tissues by the fistful, and trying to shove as many of them up their nose as possible. Whether they have seen any blood or not.
After I realized we had decimated 5 boxes of tissues in 3 weeks, I put my foot down.
I'm not sure what triggers the desire to race madly to the tissue box, but I think it's going around.
Now, if only the kids who have boogers running down their faces would catch on to the trend.