It'll be interesting to see if that improves the general travelling environment. I've said before that I usually avoid travelling in a quiet carriage as I find that they are very rarely full of passengers who are all obeying the rules and when someone is making a noise it winds me up no end - and I'm fed up with telling them to stop. So, I'd rather travel in a normal carriage and put up with a 'reasonable' amount of noise - and if it get too much (babies screaming, loud phone conversations, etc.) I can then put on my headphones - at a reasonable volume - without fear of breaking the rules.
In my opinion part if the problem is that the announcements relating to the rules for noise in the quiet coach are not consistent- I am really talking about the
PA▸ announcements mainly here just giving my experience of
FGW▸ services
So for example one
TM‡ may say "please refrain from using mobile phones completely" whilst another may say "please keep noise from mobile phones, conversations,etc to a minimum"
Having said that I'm with you II, I tend to avoid the quiet coach on an
HST▸ set for the reasons you state, and also because in coach B you get a choice of doors to exit from which makes a difference on busy services