anyway my two cents on the matter.
1.) Trading with pets is just retarded. What are they going to be? Your extra backpack? So in the end just kill them and grab all the stuff?
2.) "IF" somehow she did trade with her pet and the disk was given to the pet, "THEN" she should be able to kill the pet and get whatever it had in its inventory. Because this isnt like an item poofing into existence which is I am sure what happens when you get stuff off mobs. Its about an already existing item being put in a place somewhere in reality. I.e a pet's inventory. It would be like me putting stuff in the bank. SO if that is not the case now that you can get things from dead pets that you traded to them previously it should now be.
But seeing as how it's almost next to impossible that she could have mistakenly traded with her pet. I am not inclined to believe it was her fault in anyway which leads me to number 3.
3.) Funcom you already admitted it was in the logs. Just reimburse. Its not like they did anything illegal. When you get right down to it, its because of your software bugs, that made this happen. So fix it!