This topic is very much in the news these days in the sports world. The US National Football League was sued on behalf of 4500 former players who are suffering from various forms of dementias, neurological disorders, etc, as a result of repeated head trauma. The original suit was settled for US$ 675,000,000, but the case has been reopened on appeal because that is not nearly enough money to pay for the medical expenses and long-term care cost of the victims.
I think the iSU will come up with a rule at its next congress. If you get knocked unconscious in warm-ups, you don't skate.