I understand why you suggest these solutions... but 3 of them would help, sorry.
1st. Lock the avatars on the list and investigate them, their origins etc.
Would work. I personally believe only very few scammers are reported though and you can't lock an avatar if you get only 10 complains: a soc (or especially PILOTS!) could easily lock an unwanted avatar, as it's easy to get 20-30 firends to complain about an avatar.
2nd. Make a webform that works with your account databse so people can't actually register multiple accounts.
So you enter false data, what most people do anyway, WOuld not help anything.
3rd. Get pro-active on scammers. Offer rewards for people sucessfully reporting scammers that are backed up with proof (screenshots and chat texts).
I can photoshop the names in a few minutes, chat logs are even easier to fake (one find+replace does all). This is never a proof.
4th. In world reporting system for scams, harassments etc and at least one official avatar online 24/7
Best idea but would not work EVER. Why? Because ppl are already spamming the support with stupid things like "uuuuuh, I spent 100 PEDs and got only 20 PEDs loot, this is a bug". They would yell for support everytime they think they spent 50 PECs too much when trading.
Sorry to say, but in EU are way too many stupid players that would block MA from doing a good job like this.
Solution:
Everyone who starts the game the first time and the 5th time (as a reminder) has to go through a tutorial. Where it shows how to trade. Where it tells what TT items are. etc. Where it shows examples of scams and how to avoid (no, noone can color armor!).
Why they don't do it?
Because all new players would get scared before even playing one second. And it also would give a lot ideas to ppl about scamming, so you would grow a whole new generation of scammers.
Unfortunately MA can#t do anything in advance, they can only react. But the reaction should not be so stupid and so slow as it is now
.