Frontier labs are not a monolithic entity.

There is a clear self-verification/difficulty ramp in cybersecurity, and it is a very valuable as a skill both offensively and defensively. So it is absolutely certain that someone, somewhere, will use reinforcement learning to make models very good at this, once coding agents exist.

Even if you are only interested in using this defensively in practice, you can’t really understand it without knowing how both sides work. So if you want to defend yourself, you need to train for it (or pay for someone who has).