The primary cause of information leakage through email is when emails are inadvertently sent to the wrong person. What measures has everyone been taking to prevent this kind of thing from happening?

I have, on occasion, received email messages which may only be a few lines long, but which are then followed by a signature and a ten-line disclaimer.

Here is a typical example:

“This e-mail is confidential and may be protected by legal privilege. It is intended for the named recipient(s) only. In the event that you have received it in error, please notify us and then delete all data. The viewing, using for private purposes, or disclosure to a third party of any emails sent in error is strictly prohibited.”

Rather than being a disclaimer, statements such as the above example read more as if senders are indirectly aiming to exempt themselves against any liability for information leakage, due to their mistake, by directly imposing obligations on the recipient.

So, do such disclaimers, which frequently feature some rather high-handed language, have any effect at all on reducing the risk of information leakage due to misdirection of emails?

As a rule, contracts are formed on the basis of agreement between both parties. However, in disclaimers such as the one above, it is simply a unilateral declaration by the sender and it is certainly not the case that the recipient has accepted it. Mere receipt of the email cannot be interpreted as acceptance. Therefore, just because you have included a disclaimer, it does not mean that any sort of contract has been formed between the sender and the recipient. The sender who made the mistake cannot impose any duty to contact them on the recipient, nor can they seek any damages from the recipient for having read the message.

It can therefore be said that the effect of disclaimers, as a means of reducing the risk of information leakage, is virtually zero. However, there is also the view that disclaimers can be used to kindly request the cooperation of an innocent recipient. In that case, it would probably be better (at the expense of appearance) to place the disclaimer at the head of the email.

Incidentally, lines such as “We accept no responsibility for any viruses contained in this message” may also appear in disclaimers, which, unlike the previous example, is a direct attempt to indemnify the sender; however, this too carries no legal force whatsoever, and such one-sided statements are akin to telling the owner of a house you have accidentally crashed into that “it is not my responsibility”, demonstrating an overly selfish attitude.

(Translated from the original Japanese)