I really don't understand this concept...In the 2nd book...harry potter and the chamber of secrets Harry got an official warning saying that he is nt supposed 2 do magic...nd dat 2 jst coz a hse elf did some magic... So it means that the magical department doesn't actually knw who did the magic...they only knw dat at a perticular time magic waz done in a perticular hse or place...So in that case if Ron or any other kid frm a wizard family does magic the departmanet won't knw who did it...It cud b his father or anyone who cn legally perform it...This is something wch I have alwayz wanted to knw...😕
I hope you cn understand what I wanted to imply...😛