Splitting Costs of Flying a Club Demo Ride?

Here is the basic scenario:

A non-commercial glider pilot is a member of a glider club. This pilot pays $600 per year to be a part of the club and flies on average only 10 or so hours per year. That of course equates to a cost of $60 per flown hour.

Let's say this glider club member then takes someone interested in gliding on a demo ride for an hour. The tow costs $60.

To stay true to the FAR's so they don't act like a commercial pilot, from what I understand, they are allowed to split the cost of the flight. OK, that is fine. Can they only split the cost of the tow or can the demo passenger pay for the full tow because the pilot is contributing $60 already to be able to make that flight with his club dues?

You can see where I am headed. My presentation about gliding to the local EAA members here last Friday was a raging success! Thanks to all who sent ideas and your own presentations. They were all so very helpful and were used a great deal.

Near the end of the presentation when everyone was feeling the love and seemed excited about soaring, I passed out a club glider demo ride sheet that said they only need to pay for the tow if they were really interested in seeing if soaring was for them. We got 21 pilot sign ups! Many came up after the presentation and were talking excitedly about wanting to try out the sport as they have always thought about it but never had an opportunity. Awesome!

Now the club needs to figure out how to best facilitate actually doing all these flights. I really hope it isn't only the instructors or commercial pilots who can give these rides. They need to stay busy with their current and new students. I see this as an amazing opportunity for the other club members to have an chance to step up and take one of these people on a ride this year and hopefully some of these pilots will decide to go ahead and transition over to gliders and join the club. This seems like such an easy model for club growth.

Thanks as always for your help and encouragement.
Bruno - B4