Under age magic - just wondering?

[justcarol67]

No: HPFGUIDX 188331

Carol earlier:
> > 
> >The Weasley Twins took care not to perform a spell when they used magic on a Muggle (and, yes, they clearly planned that little stunt) so that the magic wouldn't be detectable.
> 
> 
> Marianne:
> 
> ????  Don't remember that one.
>
Carol responds:
Sorry to be unclear. I was referring to the Ton-tongue toffee--they clearly intended for Dudley to take the bait, and he certainly was the victim of their magic, but since the spell had been performed in advance on the candy (which, perhaps, also involved a potion), the MoM couldn't detect the magic they'd performed on a Muggle.

Carol, who mistakenly assumed that the reference would be obvious