Careful with the “allowing people to swap boats”.
We have a growing number (I think its now grown to 2!) of people at our club with 2 boats. They sail one in light winds and the other in strong winds. Allowing both these scores to count in a series totally beats the handicapping averages.
HOWEVER, we DO allow someone who has CHANGED their boat to count both the old boat and the new boat scores together.
Its all a case of wording the insructions to encourage the behaviour you want: fair racing, when people are encouraged to race more often, and encouraged to improve their boats.