My boss crossed off that section of his contract when he worked for Booz Allen, and nobody made a peep.
I doubt everyone can do this, though.
At the same time, it's not necessarily part of a broader strategy to which the company is firmly, if quietly committed, and which they'll stick to, even as the costs of doing so escalate.
If the baseline cost of finding and hiring the right people is at all significant, economizing by lowering resistance is a no-brainer. Just treat this stuff like default settings from a useful, if not totally UX-savvy provider of software, and don't raise any eyebrows unless you get unexpected and seemingly arbitrary or mindless pushback.
I also got them to OK my ongoing participation in OSS.