Can they bill me after I'm gone?

I had 2 days off last week which were taken after I turned in my payroll sheet. Some how they payed me for those two days still. I don't think they will ever realize they're mistake. I'm getting laid off around August 31st which is 2 weeks. If they realize their mistake after I'm laid off can they bill me or hold me liable for not saying nothing even though it's their mistake?