I saw what I consider to be the epitome of money-grubbing "charity fun run" about five years ago with the "Ugly Sweater Run". They blatantly advertised that there would be no clock, no results, and it would be "about 5K/3.1 miles". For $85. On a private road that was unlikely to require any permits or even much traffic control (Remlinger Farms, for those familiar with the Seattle/Carnation area). I've run plenty of 5K runs with awards, traffic control, support, timing and placing for $35 (and this old man thinks
that's high).
But wait, you might ask, what about the charity? Toys for Tots. Bring your own damned toy, because the organizers sure as hell weren't giving the little shits any toys. None of the money was earmarked for the charity, right into the event organizers' pockets it goes.
That's the most egregious example. Other examples abound to solidify my belief that charity fun runs are a racket. Write a check directly, and go find a run that isn't trying to bullshit you with a coat of "it's for charity".