You, right there, go call 911

One item that stuck in my mind during a first aid class during boot camp was how to direct someone to call 911.

"Somebody call 911!"

"You, in the black shirt, go call 911."

If something isn't the responsibility of a particular person, it will not get done. Everyone assumes someone else will do it.

The same thing applies to software, and especially maintenance issues. If you say "hey, guys, looks like the app is down", it's going to stay that way. An open ticket not assigned to anyone is only useful if that is implicitly assigned to the product manager to review for the next iteration. If the app is down, then the right action is to open a ticket, and say, "hey, the app is down, it looks like the database, Joe, that's your area, here, it's your ticket". If Joe determines that the database is down because someone tripped over the power cord, then Joe can assign the ticket to Larry in ops, but every step of the way, some one particular person is responsible for that task.