Of those with interest, if any of them are programmers or have the slightest curiosity about what all those files are for, they're abundantly competent to pull off this hack. Not necessarily the automation, but they can make it happen.
but now the developer is going to have to rewrite their system to mitigate this
This hack was literally waiting there for anyone who cared to look. Please don't tell me you've forgotten this: http://img820.imageshack.us/img820/1641/itsfinetrustme.png
Sure it does, enough, anyways. I'd be willing to be the majority of players don't cheat and have no interest in cheating.
The remainder that have an interest can be futher subdivided into "no idea how, no idea how to begin", "no idea how, but curious enough to look", and with the addition of the author's post, "no idea how, but a google search away with step by step instructions".
It's a cool hack, don't get me wrong, but now the developer is going to have to rewrite their system to mitigate this, and in the meantime, there are going to be a bit more dicks in the world.
But at least there was a nifty wrapper released- I just wish it wasn't for black hat purposes ;)