How to Catch an Apparator?

[Ravenclaw Black]

No: HPFGUIDX 73939

I was just thinking of something, on page 101 of the US edition:
 
They fell silent.  Footsteps were coming up the stairs again.
"Mum," said George, and without further ado there was a loud crack and 
Harry felt the weight vanish from the end of his bed.
 
It seems like wizards can apparate without having to say a 'magic word' 
like other spells.  This leads me to believe that apparating can be done 
without the use of a wand, which brings me to my question: how do you 
catch a wizard who can apparate?
 
Like when Black was first cornered by the ministry, why didn't he just 
apparate away?  Or when Death Eaters are in a fight going badly, why not 
just apparate out of there?  I keep thinking of the opening scene in X2 
with nightcrawler teleporting all other the place to get past secret 
service men and into the oval office. 
 
Anyway, the more I think about apparating, the less of a good idea it 
seems to be something from a writers point of view.  Especially if 
words/wands are not required.
 
Any thoughts?

"Colin"


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