Support! However, a potential technical Problem with this
If someone messed up your groups, there would also be an option to reset your groups to however they were before that person made their first change.
How would this work, if:
1: You sent a trade before you logged off
2: Someone messed up your groups
3: Trade with a pet from that group was accepted
4: You log on and reset group organization.
I assume it would realize that that pet is not there and not put it there, but how would it know what your groups looked like before and what pets to skip over?
Also why would anyone "mess up" your groups if you have to trust them/add them to sort the groups anyway? Couldn't you hire someone else to re-sort the groups then, and leave a bad review on the person who messed up the groups' sorting shop, like "This person messed up my groups! Don't use this service!"
So I feel like the "undo" sorting isn't necessary, but if it can work it would be a welcome addition. I just wouldn't want the "undo" button to be what holds this suggestion back