Interesting Ethical (Business) Question

This one is for any trainers or coaches who work with clients privately. I'm not entirely sure how something works regarding protocol, so I'm curious what everyone's take is on this.

Let's say you're contacted by a professional athlete who's looking for a place to train (and a coach to train with) for the summer. He tells you where he's going to be, and you know a few guys in the area you'd recommend (because he won't be in your area, and you can't do it yourself).

Two things to consider:

1. The guy is sort of a "name," and has unlimited financial resources. I know you're supposed to charge everyone the same amount, but this would be a pro athlete who'd want the "deluxe package," whatever that might be.

2. If it wasn't for your referral, this particular athlete would never walk through the door of the gym you recommend, he'd never work with this particular trainer, and said trainer would never make a dime.

With that said, is there customarily a "finder's fee" in situations like this? I recommended athletes to guys before and never thought about this, but now that I'm a greedy S.O.B. who thinks about nothing but money, I'm envisioning the amount of cash that's going to be changing hands and I'm curious to know people's thoughts on this.