I read the article you linked to, but the method it describes would surely only work for a few minutes, or until the battery level goes down? Having said that,

I read the article you linked to, but the method it describes would surely only work for a few minutes, or until the battery level goes down? Having said that, I do get that battery level has some potential as part of a very short-lived fingerprint, and I really don't see the need to expose this information to remote sites.