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]~.