Hence why I'm beginning to lean towards a simultaneous log in service, it would put to rest these kinds of complications (and others that may arise with the new ability to transfer EX items between characters on the same account).

I also suggested only a "separation" method of transfer service where the newly transferred character is placed as the first character on a new account... this would disallow "merging" accounts (which would cause profit loss in a case like you mentioned, with 5 separate accounts).

Still, if a separation service is included, I see no reason it would hurt subscriptions. I don't suggest implementing both. Thus even if an account "merged" 5 separate accounts, they still couldn't play simultaneously.