Actually, about a year or so ago, i found out a way to do it. I was throwing explosion potions at some of my guild members in tram, just for the hell of it. Then one ran past me and stole an explosion pot right after i double-clicked it. After he stole it, the countdown appeared on HIS screen, then the pot exploded in his backpack. We tested it further, and if it's done in fel it will hurt the thief who stole it. Too bad the only purpose it serves is getting back at another thief stealing your explosion pots, lol.