Had a moment last month where I opened a ticket, started typing out a whole explanation for a refund policy question, and right at the top there's this little banner saying another agent's already on the same ticket. Turned out my coworker had literally just submitted almost the identical answer thirty seconds before me. Would've looked pretty unprofessional sending the same thing twice to one customer, so that warning saved me from an awkward moment I didn't even know was coming. Review collected by and hosted on G2.com.
It doesn't always catch it if someone's on their phone instead of the browser, had one case where a teammate replied from the mobile app and I had zero warning she was even on the ticket, found out only after I'd already hit send on my own reply. Review collected by and hosted on G2.com.