Glenn, I don' know if this is what Chris is saying or not,

However, what Chris is proposing (unless I'm completely misunderstanding him) is this:

Rider A enters three races, all on Sunday
Rider B enters three races, one on Saturday and two on Sunday.
Both pay the same entry fees, but Rider A has to pay for Saturday practice and Rider B doesn't.

Does that seem fair?

It does not seem fair, I think this is how it should work....

Rider A signs up for 2 races on Sunday only and practice on Saturday
Rider B signs up for 1 race on Saturday and 2 races on Sunday

Rider A should pay for practice on Saturday
Rider B should not pay for practice on Saturday

Or, just give rider B one practice session right before lunch or something. It should be like the endurance race.