Reborn on the other hand had a way WORSE issue during winter of 2019. The very first russian side to dominate the server had to eventually left it after admins leaking the exact time of Baium respawn to unepic said and cancelling the olympiad period which would have resulted in russians taking 90% heroes over unepic.
Valhalla age has paid streamers as a part of their promotion program. To reduce the expenses they are just paying them a some part of the salary in form of ingame currency and keep the eyes closed while they do heavy RMT.
I've heard admins of some paranoid servers like l2reborn and l2etina ( rip ) used some scripts to trace exchange / freighting of adena so it turns out that the trade shop is being the safest so far