Source: http://pso2.jp/players/news/25837/

This probably won't apply to a ton of people and has probably been discussed around already but, just in case, I am posting it on here.

SEGA is temporary/permanently banning Multi-Accounts that are being used for malicious purposes.
There are 752 accounts that have been banned following the announcement.

It is not specified what counts as "malicious" but, it's easy to suspect RMT is a big one. If you are playing with multiple accounts and transfer meseta from one account to another I would take precautions as to what you're trading to make it not seem obvious (Ex: 1 Grinder for 1mil+). It's unclear how hard SEGA is cracking down on these malicious acts but, It's worth not risking losing accounts if you're recklessly trading tons of meseta between the accounts.