How can refunds be prevented after an event has finished?

Is there a way of preventing purchaser initiated refunds after a specific event has completed? As it stands my testing suggests that it’s possible for a purchaser to trigger an automatic refund after the event has completed.

I’m aware it’s possible to turn the “Enable Refunds” off, or set an end date in “Allow refunds until:”. However, what if there are multiple overlapping events? The refunds option is a global rather than event-specific one – so if refunds is turned off then the refund will be turned off for all events, not just the one that’s just finished.

Perhaps there’s a setting I’m missing somewhere.