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As google allows to create a single account and google recorded the IP address of computer.
If two persons uses one computer then definitely google can track this, thay should understand that a person has two adsense accounts & they can suspend both of accounts.
sorry for my poor english...
I manage at least five accounts from one computer, one for me, one for my company, and three for clients. Never had a problem.
I would imagine if one account were ever banned then the second account would also be banned as a related account. I would worry about managing accounts I had no control over through the same computer for that reason.