the following may sound obvious to many, but is something that newcomers aren't aware of too often.
when you give a free invite to help someone on fst, here's what can happen:
the person you invited may open a trade thread and trade his new account for something else just hours after he created it. you will end up with a trader in your invite tree, who you never wanted to invite. a complete different person, a stranger, a cheater, just anyone. keep in mind that on most trackers you're responsible for the person you invite.
your invitee can also give away the account to someone else, which has the same result.
now you might say: wait a minute, that's pretty lame. is there something that fst is gonna do about that?
answer: no, this behaviour is perfectly fine with fst rules. there's nothing that can be done about it.
in fact quite the contrary. the trader wo misuses the account you provided him with will be protected and supported. fst offers middlemen for his deal to make sure everything goes smoothly and he gets what he wants.
on top when his deals go wrong, he (unlike you) can report his trade partner for being a scammer and fst will punish him according to the rules. fst rules protect betrayed traders, but they do not protect you. happy times for the trader, tough luck for you.
please keep this in mind the next time you're going to invite somebody on fst.