Unfortunately I've been in organizations where this was necessary for exactly that...

Exec Manager (wanting to save face in next exec meeting) - Why did the team do that? It obv didn't work. Who's fault is this?

Product Manger - Remember we all signed off on this PRD saying we would try this approach? We also included a couple of alternative options we can explore in case the primary approach wasn't as effective as we hoped.

Upper Manager - ... (after a moment) Ok then, let's explore those alternatives.

Engineering Manager - whew

PRDs _esp those with sign off_ can cover your ass.