This works only if the boss is a nice and reasonable one.

When I informed him our dependencies (from other teams) were not ready and there would be delay in delivery, my former manager said: "Sorry, but I can't change the deadline, they (the upper management) made this unchangable."  On the other hand, he fabriced the project data/time for tasks we were not assigned.  It took courage to protect one's team from the upper pressure, some people just couldn't do.  I chose to leave.