“IF THIS e-mail is received in error, notify the sender immediately.” “This e-mail does not create an attorney-client relationship.” “Any tax advice in this e-mail is not intended to be used for the purpose of avoiding penalties under the Internal Revenue Code.” Many firms—The Economist included—automatically append these sorts of disclaimers to every message sent from their e-mail servers, no matter how brief and trivial the message itself might be.

E-mail disclaimers are one of the minor nuisances of modern office life, along with fire drills, annual appraisals and colleagues who keep sneezing loudly. Just think of all the extra waste paper generated when messages containing such waffle are printed. They are assumed to be a wise precaution. But they are mostly, legally speaking, pointless. Lawyers and experts on internet policy say no court case has ever turned on the presence or absence of such an automatic e-mail footer in America, the most litigious of rich countries.

Many disclaimers are, in effect, seeking to impose a contractual obligation unilaterally, and thus are probably unenforceable. This is clear in Europe, where a directive from the European Commission tells the courts to strike out any unreasonable contractual obligation on a consumer if he has not freely negotiated it. And a footer stating that nothing in the e-mail should be used to break the law would be of no protection to a lawyer or financial adviser sending a message that did suggest something illegal.

So why are the disclaimers there? Company lawyers often insist on them because they see others using them. As with Latin vocabulary and judges' robes, once something has become a legal habit it has a tendency to stick. Might they at least remind people to behave sensibly? Michael Overly, a lawyer for Foley & Lardner in Los Angeles, thinks not: the proliferation of predictable yada-yada at the bottom of messages means that people have long since stopped paying any attention to it.