If it's technically possible for an agent to circumvent a security policy, it should.
Telling it not do something via AGENTS.md was never secure. This is just an expedient way of pointing out all the flaws in your setup. And if it's not even doing it for nefarious reasons, just trying to do what you asked of it, I think it's fair.
I've even found it genuinely helpful. I've sandboxed my Codex so it can't run certain things. Things I'd actually like it to run but I've restricted it too much, so it finds clever ways of doing it anyway.