Wait....then how can we distinguish them?

[Pride]

Recently, I got to know that there is a command, e.g [i/F8TH63:999] which allows you to put the image of an item in the chat. My question is that, how can we distinguish a hacker and some one who is using that command? If some one says that I am selling 999 luminite, 999 Nebula fragments, 999 solar fragments -etc- then how can we prove that he is a hacker, because there is a possibility that he is using a command like [i/F8TH63:999] to trick people. 

Thanks!
Wubwub