My query would be how ordinary rail staff, let alone their Unions, could have not raised this as a matter of simple common sense. How long has it been the case - years, decades ?
There are many rules that many of us believe shouldnt exist, are out dated, and yes, sometimes plain stupid. However; that is where you need to take the professional approach. Rules are there for a reason and often reasons that we cannot see. As a Metro man I always thought the "4t's and a sugar" rule a little odd. I'm always pretty close to a signal or station so why is anyone walking a mile and a quarter but then, I went over to 100mph lines with signal spacing and stations that are miles apart. The professionalism in us also realises that the rules are created by people with much more knowledge and information that we have. There is decades of history behind the rulebook and again, someone else sees something we don't. Not forgetting one of the basic rules for a safe working railway has always been and should still be, the rules are there to be followed. Not just from a liability aspect but everyone working to the same rules keeps us safe.
There are always going to be cracks and scenarios that cannot be accounted for. The rulebook has evolved over time and still continues to change on a regular basis. The fact that this is changing in December shows that evolution.