Well, first, its pretty much in the DNA of OpenBSD to try security implementations like pledge. Second, and much different from what SystemD just did, pledge d

Well, first, its pretty much in the DNA of OpenBSD to try security implementations like pledge. Second, and much different from what SystemD just did, pledge does not affect any program that doesn't use pledge. From an external caller point of view, each changed user land program should act in the exact way that it did before the change. A programmer can safely ignore pledge and nothing has changed for them. A user can safely ignore pledge as it shouldn't change their usage. If Linux (I would guess more appropriately the maintainers of the GNU user land) tried this under those conditions, it would still be an internalized change that shouldn't affect anyone outside the project except in the positive as an exploit mitigator. The bottom line is: OpenBSD is not requiring changes in other developer's programs or in user usage to continue to run in the same way they have run in the past.