その音は、かならずしも心地良いものではないのでしょうか、blow the whistleという成句にしても、この"whistle-blower"にしても、俗語として、内部告発（する）、密告（する）、という意味があります。
Office Depot whistle-blower getting paid by competitors
Fort Myers resident and Office Depot whistle-blower David Sherwin is receiving money from competitors of his former company.
Sherwin said he was fired from his job as a senior Office Depot account manager after alleging the company was overcharging thousands of government agencies and nonprofit organizations across the country by hundreds of millions of dollars.
After being fired, Sherwin began a campaign of e-mails, faxes and telephone calls to hundreds of government agencies. Since his campaign began, four federal agencies, six state attorneys general and several state and local government auditors have launched investigations of the company’s government contracting practices.
Office Depot made no statements for this story and declined a request for an interview. However, in a late-October statement, the company called Sherwin’s motives into question.
“His negative campaign against Office Depot – which is often repeated by our competitors, who we believe are funding his efforts – is littered with misrepresentations, omissions and absurdities,” an e-mailed statement said.
(Naples News. November 22, 2009.)