Seen or Caught numbers effecting shiny odds?

It seems like most people who find multiples of shinies in Pokemongo during an event are finding them because their caught number for that Pokemon is going up. They spend hundreds of dollars I assume on boxes and pokeballs and catch everyone.

Maybe if you just click on the Pokemon and your see it then run like I do since I don't have a lot of pokeballs you get nothing.


Or are they using some tracker to find the Pokemon?

I don't believe this is the case - quite a lot of research has been done into this on the Silph Road and it's basically just the same odds no matter how many you've caught. It might seem like more = higher chance because they're so rare to find that it usually does take a couple hundred before you come across one, but it's pretty much confirmed that this isn't the case.