Having to deal with this situation on other platforms i find it easy to identify. You will also (if you know what your looking for) see fake steemit cards edited into the image, and they achieving verification in the eyes of many steemit users. Unless users are educated somehow of the basics things to look for with any form of theft, then it will continue and only get worse. I can only be 100% sure the account is legitimate if i see that user in a video with steemit cards etc. The other cases where the account is verified with another user which is known to the community.
But these "Serial Fraudsters" will always slip through unless we as a community become more aware, and like Anyx has stated a "Proper Verification Channel. I would like to offer my help voluntarily if i can. I spent the better half of 2 years everyday hunting thieves in a virtual world that were stealing images/files creating fake accounts etc. It is something i enjoy and get satisfaction from.