I finally plucked the courage last night to have a look at this thread and my god, how I now hope I didn't.
I was watching "Air Crash Investigation" last night and in one episode, part of the commentary when describing the chain of events that unfolded went something like this,
"Modern planes are so highly automated that everything from take-off to landing can be done through computers. On most flights, minimum pilot intervention is required throughout the journey.
However computers cannot handle scenarios they are not programmed with. When these unfamiliar situations develop is when the pilots really earn their salary, putting their years of training into good use."
It got me thinking. Don't guards' roles have a lot in common with that, albeit on a more frequent basis, as new situations develop constantly on the railways? In day-to-day running, when everything goes smoothly, it may not be so significant that anyone other than someone who can move the train is onboard (grossly oversimplifying it of course), but it is when things start to go "wrong", which could even be minor things such as an alarm being set off somewhere on-train, a passenger being unruly or luggage being stowed in such a way as to be blocking escape routes, or major events such as the driver being incapacitated, that a guard's importance shows through. The benefits of a guard is also not restricted to them being able to recite the rule book and remembering what instructions are contained within, but also using their professional judgement (on the basis of weeks, months, and most likely years of training) when an unfamiliar situation develops. Would a person not trained to the same level of competency deliver the same standard of performance? (If the OBM will have the same level of training and be given the same responsibilities, possibly less the door duties, they will likely command a very similar level of remuneration compared to the existing grade, then if they are proposing a higher level of staffing, where is the financial incentive?)