This makes it sound like "with enough time and patience anything is possible"
But the steps described aren't even what i would call a hack. You could do them by accident if you were trying to log in to your own account under someone elses computer using chrome, in less than a minute if you're quick. It requires no technical knowledge and can be done with time to spare during someone's bathroom break.
Here's the process in a nutshell:
1) logout of their account in chrome.
2) login to you're account
3) lie and say you were the previous per person
This isn't a hack. There is no hack! This is a very small step above the "honor system" as your security!
Maybe they could make you enter the system password for this action too like they did with saved passwords (earlier, saved passwords were visible in plaintext but now you have to enter the system password to see them)
The response smacks of an attitude that "once a machine is even a little compromised it's not our responsibility what happens. Physical access is a compromise, therefore we don't have to fix our own loop hole."
This is like a safe company saying, "Well, of course someone that breaks into your house can also open the safe by saying, I'm the owner out loud."
Because Firefox doesn't have sign-in and sign-out like Chrome does, the principle of least surprise kicks in.
When the barrier to entry for "hacking" credentials and sensitive information is so low, the world's really in trouble...
