From the rules section of TW, I think the bolded and underlined bit kind of answers your question.
§3) Account sitting
I. This is a temporary replacement to the account owner, both are equally responsible for actions taken by the sitter, and will be punished accordingly should any breach be found.
II. Rule 2, paragraphs II. and III., must be adhered to, as if the accounts in question were sharing a connection.
III. Account sitters that intentionally destroy or seriously damage an account they are sitting will be punished. This includes suiciding troops, downgrading buildings, or supplying information about the account to a third party.
IV. Sitting an account for the sole purpose of supplying resources to others is forbidden.
V. Any account sat for more than two months in a four month period will have the sitting ended unless there is good reason (i.e. Owner away in forces) about which the account owner has previously notified the Ingame Staff in a support ticket.
