iCloud Keychain syncing is a great feature in Mavericks, but the Internet Accounts settings syncing should really have an option to disable it.
My work Exchange account set up on my company MacBook Pro syncs its account settings to my wife's Mac Mini, so as soon as I set up the Exchange account in OS X Mail, its settings automatically propagate to my wife's Mac Mini's OS X Mail, and as soon as she opens Mail, the Exchange account starts downloading email from my company's Exchange server.
Apple sometimes strikes me as a company that lacks any common sense. This is a major corporate security breach. Corporate computers have encrypted hard drives, but home computers don't have to. So, aside from the fact that it's a major inconvenience and a pain in the rear, it's also a serious breach in corporate security. How is it that Apple didn't put a switch in iCloud Keychain settings to have this feature enabled or disabled?
Like others stated, if I try to remove the Exchange account from my wife's Mac Mini, it automatically removes it from my corporate MacBook Pro. Yes, it's possible to make the Exchange account inactive on the Mac Mini, but that requries extra steps, and doesn't take away the fact that my corporate email account is automatically set up on my wife's private Mac Mini via the iCloud Keychain feature.
Another downside of this feature is that both my corporate MacBook Pro and my wife's Mac Mini inundate the logs with the same message repeating itself every couple minutes that there's an account that is deleted but not among the deleted accounts. So, it seems that there's some sort of old account that was once set up and then removed that is stuck in the iCloud keychain, and even though it's not provisioned on any computers, it's not being removed from the iCloud Keychain syncing function. So, both Macs just get hammered with these messages every other minute.