Use this photo search engine to check profile photos. If they appear in places other than the dating site, the profile is fake.
I found several sites where the profiles were exact copies. Names, dates, pictures, you name it.
I gave it less than one month and I'm certain I will not be doing this again in the future.
here's the engine:
world wide web dot tineye dot com

This is an Interesting idea but I think your logic is a bit flawed. I belong to 3 different free dating sites where I use the same picture. I use the same nickname on 2 of them with the third having a slight variation due to someone else using the name. My profiles are not fake and I log in to each dating site frequently.

I would think if the picture was used on 3 different sites with different names and dates then I would get suspicious.