The palm-size toys - marketed as stress relievers for children with autism and attention-deficit hyperactivity disorder - have become so popular that schools throughout the world are banning them as fast as they are spinning off shelves.
"They are currently not allowed in the classrooms as we have not made a decision as to their educational value," said Clifton Preparatory School principal Victor White.
The Durban school placed a Grade 6 boy on internal suspension for two days for selling fidget spinners at school.
White said the boy was in contravention of the school's commercial activity policy and that the nature of items sold had no bearing on the issue.
Since mid-March, entrepreneurial schoolchildren around South Africa have been selling the colourful Forbes "toy of the year" - a metal or plastic shape that spins off a ball bearing - to their classmates for about R150.
Local company Stress Cube South Africa has already sold more than 7,000 of the gadgets.
A Pretoria mother, who did not want to named, finally gave in and bought a fidget spinner for her 11-year-old daughter last month.
A teacher confiscated it at school the next day.
"The teacher informed me via WhatsApp that fidget spinners were not allowed in class," she said.
Action in Autism chairwoman Liza Aziz said it was "extremely sad" that fidget toys were being banned.
"We would absolutely endorse the use of fidget toys or tools in the classroom - our autistic people feel their senses very strongly and have problems with sensory integration. The fidget helps them maintain calm and concentrate in a highly stimulating environment. It also helps reduce anxiety and in many instances can be a lifeline for our people," she said.
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