I transferred from Balmung to Cerberus for roughly five months. The servers are on completely different Datacentres. When I transferred back to Balmung I was shocked to find out that I was still on some people's friend lists. I simply showed up as 'Unable to Retrieve' during my absence but as soon as I returned everything was back in place. Given that one of my reasons for my break was due to not wanting any communication with certain players it was a rather unpleasant experience.