Actually, they are. From all the schools in Shenyang.
In case that site updates and the news gets pushed off the front page, here's the article:
1-29-05---- Shi No Note Controversy In China
Takeshi Obata & Tsugumi Ohba's Shi No Note (Death Note) manga has been a big hit and point of controversy with schoolchildren in China recently. An actual ban on items related to the work has been implemented in Shenyang City schools where it's been considered threatening. Some students had purchased Shi No Note stationary with the header "The Person's Name Written Here Will Die In 40 Seconds." Students were reportedly writing the names of hated teachers on the slips of paper. The local press mentioned "The note is a poison that creates a wicked mind".
Emphasis on the last line is mine. I'd just like to point out how incredibly appropriate it is, considering the in-manga parallels. Are the sociologists right? Is it unhealthy to use fan merchandise to mentally kill people you don't like? Also, do the schools have a right to ban merchandise for this reason?