We do not allow either late check in or check out, fee or no fee.  The only flexibility we offer is within the two hours between published check out of 11 am and check in of 1 pm.  We will allow that wiggle room without a charge provided it does not infringe upon maintance etc. 
There just isn't an upside to any other policy. Late and early fees just appear to be money grabs to many guests creating customer satisfaction issues.  We usually couldn't accommodate those requests anyway, since the sites are usually committed to others.