I tend to find the starers do so in their first session, or they started off as talked and can't switch off to switch off.
I'd say there can be three stages
1) The talkers - inquisitive or have enquiring minds. They might be isolated, lonely, have noone to listen to them who is objective and unjudgemental and want to offload their woes toclear their mind and heal.
2) The starers - sometimes they were the talkers in their first session. They might want to take their healing to the next level and for them, this is as switched off as they can be. I just let them be, it is their healing session, I smile and let them know they can chat if they wish or if they feel comfortable to do so, just gently let their eyes close and relax.
3) The zonkers - often the ones who want to feel pampered or want an 'experience' - soon as their head touches the couch they are off wit the fairies and no amount of coaxing will bring them out of it. They take the time to internalise things. I let these know that the healing is theirs and if they find their mind racing towards troubles, just acknowledge them and let those thoughts drift far away.
Starers can be disconcerting, used to make me feel a bit uncomfortable, like they weren't enjoying it or maybe I was doing it wrong - I realise now that is as much as they are able to switch off at that time - that is their healing, so just smile warmly at them and reassure them. The other two 'types' are easier to work with, technically and some do progress along this ladder as treatment progresses.
I wouldn't tell my clients to shut up - it's their healing and their choice. I will reassure them that whatever they choose it is fine. The worst thing to do is tell the little old lady who has had noone to shut up during her reflex treatment, when you're the only person she's seen all week and has been looking forward to the company. I let my students know that on exam day they need to encourage the client to drift off - as examiners do mark them down if they talk. However, in their own setting, I encourage them to see where the healing takes them and to focus on the experience most appropriate for this client at this time.