"But walking with a cocked hammerless is OK?
How could you possibly infer this?"
I do not infer it, it is what most people do, they carry a cocked hammerless with the safety on, thinking that the mere blocking of the trigger via the safety protects them from an accidental discharge. So walking with a cocked hammerless on safe is not OK by my recknoning. Hence the question mark at the end of the sentence.
I designed and made via 3D printing a plastic prototype inboard hammer SXS. It was posted here some years ago. The hammers being close together they allow easy simultaneous cocking with a pass of the thumb. But..... the quoted price for CNC machining the action stopped that idea.