Harry's Privet Drive protection

[Antonia Simigis]

No: HPFGUIDX 88415

There is a quote in OotP that I find fascinating. It's
in Chapter One, p. 5, and refers to when Uncle Vernon
discovers Harry outside the window: 

"For a few seconds they struggled, Harry pulling at
his uncle's sausage-like fingers with his left hand,
his right maintaining a grip on his raised wand. Then,
as the pain in the top of Harry's head gave a
particularly nasty throb, Uncle Vernon yelped and
released Harry as though he had received an electric
shock--some invisible force seemed to have surged
through his nephew, making him impossible to hold." 

Note that Vernon is standing inside the house, but
Harry is outside. Do people within the boundaries of
Privet Drive who try to hurt Harry get zapped because
of his mother's protection and Dumbledore's charm, or
did Harry zap him unintentionally? He is holding his
wand, after all.

Any thoughts? Are there any other points in the canon
when Harry is unintentionally protected like this
(besides the first time, of course)? 

"Antonia"

__________________________________
Do you Yahoo!?
Yahoo! Hotjobs: Enter the "Signing Bonus" Sweepstakes
http://hotjobs.sweepstakes.yahoo.com/signingbonus