My bet is that OpenRouter began steering GPT-5.6-sol users towards flex tier, which is already 50% off.

So this isn’t really a price cut. As to why, lots of possible reasons. Perhaps an agreement with OpenAI to help them drive up more diverse traffic priorities.

CSAM, and other harms, are typically detected using a set of specially trained, faster and cheaper models (and out of band matching techniques) that run before and after the main model.

Any mention in the system prompt is mostly defense in depth, and to make refusals more graceful.

Also, the system prompt, or even something reinforced on every message, is nowhere near as strong as its internal training or as an external safeguard.

If the prompt were the only protection, it would be extremely easy to produce illegal content after a long session.

Is it really that unusual? When you attach an image or a video, it gets converted to tokens you don’t see, at a rate that is proprietary to the model. You pay for those tokens, but don’t see them. Even how text is converted to tokens is a property of the dictionary, which is opaque for proprietary models.

There are features of input and output that are opaque to you, but that you pay for. Part of how model providers chose to run their service.