Email anonymity breached?

According to TECHWORLD, Canadian researchers came up with a method to identify the writers of e-mails. As high-tech as it sounds, the ideas behind it is nothing but "sniffing out patterns in their writing style from use of all lowercase letters to common typos". If it goes well, it means that the sender of an e-mail can be singled out even if sent anonymously, especially those of malicious spam e-mails.

Concordia researchers tested their system by putting it to use on over 200,000 emails from 158 employees of Enron, and were able to identify authors 80% to 90% of the time.

80% to 90%... um, sounds like a promising number. But wait, what would happen to the 10% to 20% that might be wrongfully judged as  criminals?