Rule is simple: No jewelry—includes earrings—at any time: NEVER under any circumstances. Tape over earrings similarly does not permit wearing of earrings. Metal puncture in the vicinity of the ear could result in damage to the carotid artery.
Responsibility is that of the coach, the refs and the league—we will not take chances !!
Only exception is a medical bracelet, taped on the wrist with medical condition showing.