The Milton couple whose home was the site of a massive party that police shut down Labor Day weekend did not know what kind of event would be held there, the couple’s lawyer said Wednesday. Randall K. Power, the attorney for Steve and Sharon Mathieu, made his comments outside Quincy District Court, where the couple were arraigned on charges that they sold alcohol without a permit. They are due back at Quincy District Court Feb. 28 for a pretrial hearing. The couple have not commented publicly since the party, which police say was attended by 1,500 people. The event was advertised on Twitter as the “Make It Nasty Mansion Pool Party,” with tickets sold for $15 and $20. Power said both Mathieus were embarrassed by the incident and would not host anything similar in the future.