You can already go into a friend/siblings knight Skyguarder, just log on and click on their knight, so -_- and :P

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I dont see why not, this it just 1 feature that any other MMo have, to swicht to 1 of your characters that have in your account.i dont see how that its bad.

No, because people actually share their accounts with their younger siblings (teenagers). If this was a feature, their younger siblings could just get into their older sibling's account (Or a friend).

this its not a valid argument to not make this possible, because well its even on terms of service, also its supposed you SHOULDNT dont share your account if you already do this then its your own responsability, but not because "those decide to take the risk" to share their account this feature shouldnt be added, if you share your account with someone else its at your own risk:

Account Security

Keep your account safe! - No one except you should ever know your password or have access to your account. It is forbidden to share passwords or accounts, grant someone else access to your account or access another knight's account. You are responsible for the security of your account data and are likewise responsible for everything that happens on your account, including rule violations of any sort. You can find more information on how to protect your account in this article about account security.

Your Account is Your Responsibility

You are solely responsible and entirely liable for all activities conducted through your account and/or your User ID, even if your account has been compromised through no fault of your own. Three Rings encourages you to maintain the confidentiality of your password, and reminds you that you do not have a license to let others use your account. You agree to notify Three Rings immediately in the event your password is lost, stolen, disclosed or compromised. It is not Three Rings' policy to ask for your password online, and Three Rings suggests that you never respond to an on-line request for your password. You acknowledge that although the Site, Services and/or Games may offer a feature that allows you to "remember" your password and thereby bypass the password protection, this feature makes it possible for third parties to access your account and User ID. Three Rings strongly discourages the use of the password bypass feature, which will in any event be at your own risk.

In the account security section...:
Prevention

Do not give your account password to anyone, even if they are an Game Master, other employee of Three Rings, or someone you otherwise trust. Your password is meant to be for you alone, as the owner of your account, to know. Game Masters and other Three Rings employees do not need, and will not ask for, your password.

this the same thing you did when someone suggested "to add pet food machine" in subtowns and well look they were added.

Although i still dont understand why OOO added 3 knight slots if your knight can be any class you want by swichting gear. the only thing i can imagine about the 3 slots knight reason its for Roleplay purposes.

Anyway changing knight that you have in your account without log out should be an option. after all all the accounts are personal and shouldnt be shared with someone else, no matter if they are your boy/girlfriend, brother/sister, etc. even if they are your younger brother/sis you shouldnt share your account with them, what if they get tricket by someone else and give the account info? yeah your account was compromised. THATS why you shouldnt share your account not matter who is the person you share your account.