Our algorithm determines if someone has more than one account that is pretty sophisticated. We don’t catch people 100% of the time, but we’re really good at it.
While having two accounts associated with the same person isn’t automatically a red flag, it’s something to be aware of. Two accounts often happen because someone forgot their password, or they forgot if they still had an account, or if they changed their email address. It also happens because people live in the same house and are sharing a computer. Two accounts which are significantly similar (generally looking for the same type of work) may be a problem of the person trying to keep two jobs with two different employers without each other knowing.
Two accounts with significantly different info (like, one is a webmaster and the other is a writer) is usually not a problem. Sometimes someone trying to get multiple jobs will use a “cousins” name/facebook account/photo to create a legitimate second account with a high ID proof score. You can usually identify if this is a problem when their skill sets or job descriptions are very similar.
Look at the other account associated with this one. Look for irregularities between them (like the same facebook profile used on both accounts).