Free Trial characters can't shout :0
Are you mistaking normal chat spam for shout spam?

[Chat Restrictions]
-The chat options /shout, /yell, and /tell cannot be used by Free Trial characters.
[Party Restrictions]
- Free Trial users cannot invite other players to their party.
Anyone who buys from RMT sellers is at risk of having his account compromised. And seeing how RMT is still a thing at all, it's obvious quite a lot of players participate in it. Other than that..well, RMT spam was a thing even before the free trial existed. Might be that they just went back to how they did it before - creating new characters on stolen accounts and actually paying for advertising accounts.