Well Zinx he is asking what should he do when he sees this kinda thing
But to answer the question;
I use the iBot when I host tourneys because iLLepidus made it so that it has a feature where it tracks the same IP Address from players in quene, and it proceeds to kick those players. The only problem with this is; Supposed you had a friend over and he wanted to play TB with you. You have two computers hooked to the same modem or w/e. Since those two computers share an internet connection they also share the IP Address, and in this instance would be kicking two completely different players. Not to many people are computer literate enough to know that you can just refresh the internet connection on the 2nd PC too get a new IP Address or change it via command line.
So this would be easy to implement but its not very accurate, thats the only flaw behind it.
Also yes you should report those players, that would be considered "Double Accounting" I believe...