Realistically, the rules on the mainline aren’t going to change.
What operators can control is the manner in which the rules are enforced. Some tolerate the window being open an inch and you listening to the loco, which is a sensible and reasonable way of treating people who have paid a lot of money to be onboard. Others treat you like children, not letting you be out of your seat, constant announcements etc, but then have stewards in all the gangways who are listening to the loco themselves, which the guests are presumably paying for, yet they’re doing exactly what you’re not allowed to…
Hi-vis clothing comes with an invisible force field which stops anything unsafe happening to the wearer. They're amazing things.
See also platform staff standing between the yellow line and the platform edge shouting at paying customers to get back behind the yellow line for their own safety.
Back in the real world, I went on one rail tour last year where it was remarkable how many passengers felt the sudden need to go to the toilet as we approached the bottom of an incline, resulting in a queue in the vestibule. Of course you need a bit of ventilation in there while you wait, so it's only sensible to open the drop light.
I have booked one tour this year, with SRPS so expecting mk1s with venting windows and resulting thrash.
It has to be accepted that, thanks to incidents of yester year it is no longer acceptable on the main line to be leaning out of windows, and that central door locks are a thing. What is a shame is that we have a shortage of compliant pressure ventilated stock where the smells and sounds of the traction can be fully enjoyed. This is simply a consequence of central door locking rolling out after the withdrawal of pressure ventilated stock (MK1, MK2, mk2a, mk2b, mk2c).
The central door lock systems from air con mk2s almost certainly would have fitted mk2b & c however operators were already running mk1s and few of that era of mk2 coach seemed to be preserved