On public trades, watch out for hackers or scammers who are friends with hackers. They'll get the location of the public trade and teleport in front of you and steal your item. Happened to me twice and I didn't know how he figured out where to find me. Oh and by the way, the two guys who did this to me go by the names of "Brandon" and "Cay". I got a warning from another person that they threatened to hack his account of he didn't trade. As far as I know, both are jailed. But always keep your eyes peeled!