Hi, My in laws are German citizen, they came to US to visit their grandson under a visa waiver program. They thought that the length of their stay was 3 months and not 90 days. So they booked the flights to come to US and back to Germany within 3 months. When they left I asked to see their visa waiver and saw the 90days stamps on the green paper. They stayed totally 92 days once there were months with 31 days in this period. Can they re-entry US under the VWP? Should they wait to re-entry US? Any advise is greatly appreciated.