Just looked at the MEL book. All lavs can be MEL'd (x-installed 0 required for dispatch). However, it is up to the Capt to determine if it is acceptable to go without a lav or lavs based on length of flight and other considerations. If someone flew from PHL to CUN without any lavs then they were A)a check airman B) a Management Brown-noser or C) A FOOL!!!.....that should never have happened.