[EricE]

"It’s not enough to implement redundant systems and failovers, we must monitor and alert when those systems are being exercised."

My air conditioner in my house has a secondary drain pan under it. The outlet for that drain pan is right above a main window outside. If the primary condensate drain gets plugged/fails and the water overflows into the backup pan there would be a stream of water in front of a window that shouldn't otherwise be there. They want you to be able to readily notice it as you are now at risk for significant water damage if that secondary drain manages to plug up too.

Always something worth considering when designing any system - how to make it fail in a way that is noticeable!