1.7.2, 1.7.4, & 1.8 snapshot 14w04b hopper duplication bug

A youtuber named AntVenom made a video on how to glitch the hoppers to duplicate items with lag. ( http://www.youtube.com/watch?v=UWSZOeozJsI&feature=c4-overview&list=UUK376qNDlNZZDNHsnaWuTeg) He is in 1.7 and I tested it on the 1.8 snapshot 14w03b and it still is working. I know this is going to cause problems with server that have economy systems in place. Attached are photos of me doing it in the new snapshot 1.8. Hoppers facing each other with one item in each one. I went in and out of the nether portal 14 times and the lag caused by doing so made the hopper duplicate the items in the screen shot. Any other questions please let me know.