"We are having a nice family dinner and only family was invited," Andi declared.  Her hand tightened on the table and Reggie knew that the vicious wards he had previously admired were activated.  Probably even the Floo was blocked off.  If Dumbledore wished to pop in uninvited, that was his problem.  They were not required to accommodate him.  If Dumbledore forced his way through the wards, they would either kill him -and it would be considered a suicide- or he would break the ward scheme -which was against the law.