Trial apps - dealing with refunds

If a user demands a refund after you've unlocked their app is there a way to revoke their "unlocked" status?

If you are a developer who uses the trial app functionality I'm interested to hear how you handle refunds.

Not asking how to issue refunds, that can be handled via whatever payment integration method I chose.

I'm asking what do you do if you issue someone a refund, do you just let them continue to have access?