Baltimore ? Lisa Miller arrived later than she should have for the midnight release of “Harry Potter and the Half-Blood Prince” on July 16, 2005 – a slip-up she rues to this day.

It took about 20 minutes for Miller, 26, to get inside the London bookstore where she bought the sixth book in J.K. Rowling’s juggernaut fantasy series. But before she had the novel in hand, a crucial plot point was ruined for her.

Jeff Guillaume, founder and editor-in-chief of the Harry Potter Automated News Aggregator fan Web site, poses at his home Tuesday in Ann Arbor, Mich. Guillaume plans to temporarily shut down his site to prevent it from being besieged by spoilers before Harry

“Some ‘lovely’ person drove past where we were queuing and shouted the spoiler of who died in ‘HBP,'” Miller wrote in an e-mail to The Associated Press. “It was so horrible to think of it being true that even when I read the book, I still held out hope that they were making it up!”

Pranksters pulled similar stunts worldwide. In Dallas, a drive-by spoilsport yelled “Snape kills Dumbledore!” to fans gathered outside a Barnes & Noble. A blurry, shaky video of the verbal assault can be found on YouTube.

Now, as the July 21 release of the seventh and final book in the series, “Harry Potter and the Deathly Hallows,” approaches, fans who have waited the better part of a decade to find out the ultimate fate of Harry, his friends and his nemeses are taking no chances.

But how far do they have to go? Must they close their eyes, cover their ears and scream, “LALALALALALALA?”

Pretty much.

In fact, if you want to get in touch with a rabid Harry Potter fan on the weekend of July 21-22, you might be out of luck. Readers are planning media blackouts – no computers, no cell phones, no TV, no radio. And if that’s not enough, they’re threatening to get physical.

“I’ll beat the crap out of the person who spoils it for me,” Pritthish Chakraborty wrote in an e-mail. Chakraborty, 17, who runs a fan Web site, Harry Potter Beyond, in his native Bangladesh, was spoiled two years ago when a “friend” sent a picture message to his cell phone of the page describing Dumbledore’s death.

Many fans don’t want to give up the excitement and camaraderie of a midnight release party, but they know they’re putting themselves at risk.

“We advise people – I know this is terrible – to bring headphones to the book release and put them on as they leave the store so they’re not subject to the idiot across the street screaming the end to them,” said Melissa Anelli, webmaster of The Leaky Cauldron, a prominent Harry Potter fan site.

Miller learned her lesson. She’s foregoing the conspicuous bookstore gathering in favor of home delivery and instant seclusion.

“I’m not going to go to a midnight store opening, entirely due to spoilers,” Miller wrote. “I’m going to have my book delivered first thing on (the) 21st, head round to my fellow Potter nutter friend’s flat, and we’re going to avoid all media until we’ve finished reading it!”

But for many readers, contemplating the boy wizard’s adventures is not a solitary experience but a communal one. Intent on maintaining that pleasure, the leading Potter fan sites are taking pains not to reveal key plot points until readers are ready to talk.

Anelli posted a manifesto outlining The Leaky Cauldron’s strict no-spoilers policy that drew the praise of Rowling herself. Addressing those who might want to give away the ending, Anelli wrote: “We own pitchforks, hot wax and feathers. And we’re not afraid to use them.”

The Leaky Cauldron and Mugglenet, another high-profile fan site, will regulate everything that gets posted in the days leading up to and immediately following the release. When Mugglenet does start allowing discussion of the ending on its forums, readers will have to navigate through several warnings. The Leaky Cauldron might ban talk about the final chapters for as long as six months.

But other sites are more prone to attack. The Harry Potter Automated News Aggregator was besieged two years ago by new members, many of whom picked “Snape kills Dumbledore” as their username, said Jeff Guillaume, the site’s editor-in-chief.

“They were just determined to spoil it for everybody else. We call them the worst kind of Muggles (nonmagic folk). Most of them are not even Harry Potter fans,” Guillaume said. “People do it for this perverted pleasure, I guess.”

In June, HPANA began banning newly registered members from posting anything, and the site will shut down entirely the weekend the book comes out, Guillaume said.