In the United States, students have found that they may be expelled, or involuntarily withdrawn, from their schools for many reasons. With public school safety becoming a major concern in modern day schools, it is easier to be thrown out of public schools now than it was years ago.
Hate Crimes
Causing, attempting to cause, threatening to cause, or participating in an act of hate violence.
Reasons for expulsion from U.S. schools (California rules)
Students will be withdrawn by their principals for a variety of reasons, those listed in one source include the following (Right click save for reasons)
Violence
Causing, attempting to cause or threatening to cause a physical injury to another person.
The use of force or violence against the person of another (except in self defense).
Possessing, selling or otherwise providing a firearm, knife, explosive or other dangerous object.
Committing or attempting commit robbery or extortion.
Possessing an imitation firearm.
Making terrorist threats against school officials or school property.
Sexual
Rape or some other sexual assault or battery.
The commission of an obscene act or engaging in habitual profanity or vulgarity.
Sexual harassment (grades 4-12)
Drugs
Drug use, possession, supply on campus. This includes offering, arranging or negotiating to sell. This includes tobacco, alcohol and betel.