East Japan Railway (JR Higashi Nihon) has admitted selling records of its prepaid Suica e-money and train pass cards to business firms, it was reported last month. Selling data may be no surprise in this age of "big data," but failing to inform users that information obtained from their Suica cards would be sold to market researchers is an unethical, and perhaps illegal, business practice that should be stopped.

When the sales became public knowledge, JR claimed they had removed the names and addresses of the 43 million commuters whose data they sold. They further claimed that the data sold was only "statistical information," which they said did not constitute a violation of privacy.

However, the advanced analytic technology of market researchers makes it possible to compare seemingly anonymous data with other data to determine precisely who went where and when, and what they bought. Even if it appears anonymous and technically may not be covered by the Personal Information Protection Law, selling such information without permission violates the spirit of the law.