I feel like this is the most authoritative list of the Agile rules http://agilemanifesto.org/principles.html and this rule isn't on there.
I saw that OP is the CEO of Aha.io. The ideas that Suzanne is writing about are solid, I'm just wondering where the inspiration for this post came from. Thanks!
And the inspiration came from my real life best friend who complains weekly about his product manager.