1, sometimes police officers are doing sensitive tasks that would be undermined by publicity, like meeting with confidential informants.

2, bystanders with cameras might try to get too close to a dangerous situation increasing the risk of accidental collateral injury.

3, being recorded might “overdeter” officers from acting quickly in emergencies, analogous to the overdeterrence arguments made in favor of qualified immunity.

4, immunity from being recorded is important to officers, which is why police unions lobby for it, and we would have to raise their salaries a lot if we got rid of it.