I don't think Jo has anything to worry about

You've probably seen the latest plagiarism lawsuit heading JKR's way -- if not, here's a handy summary and commentary courtesy of Teresa Nielsen Hayden (yeah, yeah, whatever). The estate of an author who wrote a short (36 page) book called Willy the Wizard are suing JKR, and they provide a handy guide to bits they allege are infringed by Goblet of Fire. Frankly, after reading it I think the only possible legal conclusion is that they are taking the piss.

No, seriously. This is the kind of ridiculous plagiarism accusation even Cassandra Claire could defend herself against. There is almost no connection between the extracts quoted and what appears in the HP books that isn't completely generic. Example: 'wizard chess'. In HP there's quite a fun elaboration of the concept involving animated pieces that participate in strategy, or at least try to (probably not unique to JKR, but the sort of thing that could occur to many writers independently), and which actually becomes part of the plot in the first book. In WtW ... wizards play chess:

Willy had been on Cloud 84 which was for Wizard Chess Players.

These were pullman-like trains made of see-through platinum, and inside the trains were chess rooms. Willie was handicapped 18. There were Wizard Chess Masters who were virtually unbeatable. Willie had made a daring move. He didn't want to watch his opponent's response and his mind wandered at the moment that Angel Sandy had tapped violently on the train window....

Wow. Feel the likeness. (Presumably see-through platinum and Scotty's transparent aluminium have a similar metallurgy.)

It's also fair to point out that to judge from the extracts such as that above, WtW is written to the sort of standard that gives fanfiction.net a bad name. The SPaG and general style are so dreadful they're often actually painful to read. The book appears to have been vanity-published, which is relevant to the lawsuit suggestion that JKR might have read it -- leaving aside the question of why any writer would model anything on this garbled prose, to a first approximation nobody has read a vanity-published book except the author and their family and friends.

Here's the extract the plaintiffs quote under the heading 'The Year of Wizards Contests -- plus!' (sic):

Willy had been clever at wizards' college particularly in ancient wizardry histoire. 'Mes amis.' A voice began to boom from the walls of the great hall. 'We are here today for me to inaugurate the year of the wizards' contests. Each of you will be given details of the competitions, prizes and penalties. Au revoir, tout a' l'heure, etc.'. Duke Louis Dix-Sept jumped onto the back of one of his panthers and Goboldyquick he disappeared, carriage and all....

Willy sat in his bath. It was here in his yellow bathroom-come-study that he did his best thinking. He lay full length....

Relaxed he was able to study, as the green treated water toned his body with Aqua Superba, a newly developed water additive from Health Clinic in Puerto Rico. This additive only available to wizards with 5 stars had the ability to drain all superstar mind-clogging pressures and re-charge the system for endurance, excitement contests.

The screen concealed the selector mechanism. Willy had fed in the contest details that he had been given at the wizards' conference and having adjusted the selector, every detail of the text was magnified so that he could peruse it at his leisure.

GAIN ENTRANCE TO LIVID LAND! AND RELEASE FEMALE PRISONERS FROM ANGRY SAM'S COMPOUND. FORTY POINTS AWARDED FOR EACH PRISONER RESCUED. Willy pressed the activator remote control and scanned the prize awards list. Wizards achieving more than 1000 stars would receive life membership of Stellar Land.... I'll be ready for a contest conference in 30 minutes. Be in your cubicles....

There were four cubicles and only three apprentices at the moment, the selection of the fourth apprentice wizard was imminent....

Poor Willy, he was really eager to organise the Rescue Plan. For two weeks he patiently pursued all the details as they were presented to him by the apprentices and he began to organise his Strategy Plan....

He hadn't much time to release the prisoners....

Bimbo-Sad-Eyes had remained on Livid Land.
His task was to co-ordinate the escape of ten female prisoners....

Soldyar fed through Willy's ear lobes the latest reports including the up-to-date Livid Land findings from Sad-Eyes. Willy had been incommunicado for two days. On the morning of the third day he called his trusted apprentices together? and outlined his plan of release. He called it OPERATION DIVERT.

Willy had arranged a meeting with Angel Leader Halo Perfectus and outlined his plan to
rescue the women imprisoned....

The Adventures of Willy the Wizard No.1 Livid Land ©1987 Adrian Jacobs ©2008 The Estate of Adrian Jacobs

Interestingly, although not part of Adrian Jacobs' Year of Wizard Contests he created this (idea shown below) in his sequel Holiday Antics.

Sitting in the cove, Willy sniffed deeply and drew into his mind Breathair Oxy-Zone. He had been taught the trick by Master Wizard Onlywheness who had been blessed by Guardian Saint Lovely Lucinda. Onlywheness had shown Willy how to breathe and on outward breath to sound silent messages. It was a question of nose muscle control and delicate lacquering of the air with thought pellets....

Holiday Antics ©1987 Adrian Jacobs ©2008 The Estate of Adrian Jacobs

Sadly, that's actually one of the better bits ...

As one of the commenters to that TNH post says (#65):

This strikes me as being in the same league as Men At Work being found to have ripped off the Kookaburra song for "Down Under".

There's about ten notes that are broadly similar, the writer of the Kookaburra song took no action when she was alive and "Down Under" was a great hit, and it's her inheritors who are rubbing their hands and saying this is going to make them millions.

Trolls. We hates them, precious, we hates them forever.

That sounds like a fair summary.