In the process described they're using metal balls - so there won't be any electric effects. The metal balls immediately conduct electrons to negate any charge

In the process described they're using metal balls - so there won't be any electric effects. The metal balls immediately conduct electrons to negate any charge imbalance. You're thinking of non-metal balls, used for other processes, e.g. https://www.sciencedirect.com/science/article/abs/pii/S221128552200622X https://www.sciencedirect.com/science/article/abs/pii/S22112...