TNT aren't very good at their jobs
They could have a bot that tracks a user's 'wrongdoings', and have it issue a warning. They can't even do that, but they can have a bot that auto-freezes users accounts? lame
It is hard to tell if there are multiple people playing on the same IP. If you are greedy though, you will probably send all the freebies to your main account and it'll be extremely obvious what is going on.
I did that many times with a couple accounts and didn't have a problem. I just got lucky I guess, wonder if TNT still freezes anybody for doing it.