What do people think about this happening?

So, I’ve not ever had 2 separate accounts and won’t until September as my brother is gonna get one this year. 
Is it possible to make absolutely unfair trades in HUT? With one account I’ve noticed you can make and offer on an auction house screen to another user. Is trading like that considered a breach of contract or say an unwritten rule amongst players not to do or is that something I just haven’t don’t. As a reminder 26’ will be my first full season playing HUT and I was curious if that was considered a faux pas kinda thing. 

appreciate anyone letting me know. 
cheers