Years back, in 2008, one ALT got in some trouble after playing hangman in class.
An article (published in 2010 in The Mainichi that many blogs have referenced regarding this story but has since been removed) was re-reported on ELT News. The contents are as below:
The Mainichi reports: 'A foreign English teacher in charge of an English class at Shumei Yachiyo Junior High School is facing criticism after it emerged that the teacher drew pictures of a person being hung (aka the game "Hangman") when students answered incorrectly in class. In 2008, a student at the school hung himself, but the teacher allegedly continued using the game regardless. The parents of the student who killed himself, meanwhile, are angry.'
'According to the parents of the third-year junior high student who hung himself on school grounds in November 2008, in his school notes there were also pictures that looked like hanging victims. At the wake for their son, the parents showed the picture they had found to their son's friend, who told them that it resembled pictures drawn by the English teacher in class, the parents say.'
Professor Kazumi Fujimori of Musashino University, a clinical psychologist and author of the book "Gakko Trauma to Kodomo no Kokoro no Care" commented: '"In these times, when there is a trend for even the media to show self-restraint in mentioning suicide, if that kind of instruction was really going on in the classroom, it shows great carelessness. Even if the teacher meant no harm, for the students, who must accept whatever form of teaching is given to them, it is similar to power harassment."
Regardless of your opinion on the hangman game, remember that an ALT can be a convenient scapegoat. The best advice is, if you have any doubt about the suitability of a game, check with the classroom teacher.