I've seen it happen either way. It looks like it's somewhat of a crap shoot right now. You can get your character wiped when a server disconnects and boots you. You can also obviously get a character wipe when joining a non-whitelisted server. I'm betting it will probably get addressed when they work on the server optimization probably early next year.

Not sure if it makes a difference, when receiving the count down and chain breaker icon, I let the countdown go for 30 seconds, then manually leave the server. Haven't lost a character that way. I have however lost characters due to joining non-white listed servers which appears to be a separate issue.

@BLFonsworth, storing client data locally would likely open the flood gates to exploits. Just need more redundant character state logging server side.