Here's a scenario: You have the password to my paypal account. The police arrest me for an unrelated public indecency charge after I urinate on the local government courthouse building. The account is then used to purchase illegal drugs from another country while I am in custody. Having no access to my account or the internet, I could not have made the purchase. The police learn of this purchase when customs detects a strong odor from a package and decide to inspect it, finding a massive hoard of marijuana and jenkem. the police are alerted and ask me, the account owner, who else has access to the account. Me, under duress and probably having shitty withdrawals, tell them everything i know about you, specifically things that might implicate you. As the only known person with access and having no alibi for the time period, you are then arrested for suspicion of involvement in an international crime ring. After searching your computer they find a VPN and TOR and then you are sequestered in a secret military prison and forced to do the chicken dance naked until you confess to every unsolved crime ever.

While this scenario might be far-fetched, hyperbolic and not really accountability per se, it is a plausible worry some people may have. Just playing devils advocate here.