We've all been there: you blind copy (or bcc) someone into an email chain, they reply all – and your cover is blown.
Well now, Debrett's, the publisher of a centuries-old guide to British upper-class decorum, has deemed the practice of bcc-ing "deceptive".
Debrett's, which was founded in 1769 and describes itself as "a source on British social skills, etiquette and style", has published an updated guide to modern manners.
Perhaps unsurprisingly, the issues of concern have changed over the past few hundred years, with this year's guide including sections on the use of mobile phones, MP3 players and "social netiquette".
But one of the most commonly asked questions involves the dreaded bcc – which the publisher says needs to be "used with discernment; It is deceptive to the primary recipient."