On urzark/gaia there is the first public enemy, called Decap14 he is the biggest scammer in the game history
BTW I don not know how to scams peoples with scroll. I can not imagine that, only if you give your scroll without nothing. Last year I traded some sh!ts and if the person ask for scroll for trade I asked the scroll price too, so you can not got scammed. Maybe there is some other way to scam somehow but I do not know what it is.
If you locked something in trade window you can not change it til unlock or get traded.