That's not realistic. Do you work with your personal laptop in a work environment? I do. Sometimes you're debugging on a co-worker's machine and they step out of the room to get some water.

This flaw makes it possible to read their web passwords in a manner which is not suspicious, quick, and not easy to trace.

If it even took slightly longer, or there was a risk of being caught attached to this action it would be far less likely for someone to casually browse another's passwords.