Underage magic enforcement

[Alex]

No: HPFGUIDX 94714

> Carol:
> <<<If, as others have speculated, the underage magic is detected by
> identifying the wand, then a child under eleven would be using 
> someone else's wand or no wand at all, and the MoM could not 
> identify the child who cast the spell. I also think (hope) that it 
> would be the parents' responsibility to monitor their young 
> children's behavior...

JoAnna:
> Why didn't Harry get a warning from the MoM during the Quidditch 
> World Cup, when Barty Crouch Jr. used Harry's wand to conjure the 
> Dark Mark?  If the MoM monitors wands, you'd think that would be the 
> case.
> 
> However, one explanation is that the Ministry didn't send a warning 
> considering that the Minister of Magic and tons of MoM officials 
> were already present at the cup (and quickly determined that Harry 
> hadn't conjured the Dark Mark, just his wand).  Or, there were so 
> many wizards at the Mark, his magic wasn't detected (I believe 
> Hermione or Ron used Lumos too, and neither got a warning).  Or, 
> since it was a life threatening situation (Death Eaters running 
> rampant), they didn't bother to send any warnings.

Alex:
Indeed...Harry is the only one for whom we've ever SEEN the Restriction for Underage 
Sorcery (RUS) being enforced. I think it's unlikely we'll see or hear about it being applied to 
anyone else, either. We learn in OP that it's illegal to use magic in the presence of muggles 
except in life-threatening circumstances...At the World Cup, muggles were present and 
when they were being tortured, their lives were at risk, so did that make it ok to perform 
magic? But earlier we see a child enlarging a slug with a wand...were muggles not present 
and that made it ok?...or was it that the child was using his parent's wand?...and so the 
RUS wasn't invoked?

A long while back I supposed that RUS was a poorly thought out plot element of Rowling's 
to get Harry in trouble at the beginning of book two. Remember that Harry's actions 
against Aunt Marge in POA should have gotten him in trouble but didn't...his actions are 
instead waived off by Fudge at Diagon Alley as he's concerned for Harry's safety in light of 
Sirius' Azkaban escape. But it still doesn't explain why he didn't get a letter...

But as Rowling has continued to use RUS (in OP, but again only to get Harry in trouble and 
bring him to the MOM) I suppose it's better thought out than I originally thought, but I still 
think it's something JKR created mainly to move Harry from one conflict to another...

Alex