I caught myself out with this today.  There are two characters used in searching that conflict with URL reserved characters, this is the less than (<) and plus sign (+).  I tried to do a recursive member search (members:[default:Adelaide]+) and found the recursiveness not happening.  ServiceAPI works around this limitation by replacing < and + with non-reserved characters.  &Lt replaces < and ~ replaces +.  So my search should have been members:[default:Adelaide]~.