Can they arrest a 11 year old for doing something?

Yes. Minors can be charged with a crime depending on the severity of the offense and the jurisdiction in which the offense occurs. There are various laws and policies in place that address situations involving minors who engage in criminal activities or delinquent behaviors. In some cases, a 11-year-old child might be apprehended by the police and taken to a juvenile detention facility or put under protective care. The specific legal consequences for a minor offender can vary based on factors like the nature of the offense, the child's age, and the jurisdiction's laws.