outstanding

イギリスでプライベートスクールに子どもを通わせる家庭を狙った授業料振り込め詐欺が頻発しており，警察が注意を呼びかけています。
outstandingというと「目立った, 注目すべき」という意味が想起されますが，加えて今回の記事のように「〈借金などが〉未納の, 未払いの」という意味があります（『プログレッシブ英和中辞典』小学館）。（Koyamamoto）

Gang pockets thousands of pounds after doctoring private school bills, police warn
The criminals changed the bank details in the letters before returning them to the letterboxes in leafy Hampstead in North London
A gang of thieves has pocketed tens of thousands of pounds after stealing private school bills from wealthy Hampstead residents and changing them to make parents pay into the crooks’ bank accounts.
The criminals have targeted a number of high-end flats in the London neighbourhood, which counts as its residents celebs including Ricky Gervais, after sneaking into communal hallways and removing letters.
They are have allegedly picked the locks of multi-occupancy letterboxes in a string of roads where three-bed flats sell for around £3 million - and then steam open the letters.
Each time they discovered one from a private school with a school fees bill inside, the thieves would 'expertly' change the bank account details and quickly return the letters to the letterboxes.
Unsuspecting parents then pay the school fees into the fraudsters’ bank account without realising the scam - until they receive a call from the school telling them the term fees are still outstanding.
It is not known how many residents have been targeted - although locals say it runs to 'scores' of victims - but police say the gang is 'at large' and that officers are investigating.
http://www.telegraph.co.uk/education/educationnews/12154047/Gang-pockets-thousands-of-pounds-after-doctoring-private-school-bills-police-warn.html