Dudley's tail in the hut on the rock

[pforparvati]

No: HPFGUIDX 160470

pforParvati:

     Hi..I was doing a little bit re-reading and a question popped in
my mind was that, In PS, why Dudley's tail given by Hagrid was not
detected by MOM? Why they needed to cut it from private hospital?
Actually it should have come under muggle abuse and should have been
repaired by MoM. Was it because Hagrid's wand is broken? In that case
criminals /expelled students whose wands are broken by MoM may perform
magic without getting detected.
We all know that there are many faults in wizard acts and the way they
detect magic, but still I am curious about this. Does anybody know
canon explanation about this mentioned in any JKR interview...?

pForParvati