Update - Unscheduled Server Maintenance 1/1

From the Nexon forums:

From what i understand if you had a large number of certain high value items you may have encountered a trade ban so the GMs could check if you got them legitimately or if they were duped. I assume something in you inventory set off the automated system. They will check your case and unblock you as soon as they determined you weren't involved in the hack.

Except that doesn't explain why some dupers still had shops with stacks of AEEs and boss nebs after the maintenance.
Unless, as before with the chaos scrolls (?), a stack of 100 is suspect, but 20 stacks of 99 is not.