Reasons for sending an email (protocol) guidance / list

No doub't this has been raised before and I can't see the wood for the trees.

For the majority of members everthing ticks along nicely (meters aside boom boom) until something is required.
PP emails a member, or the member visits the community page and see's that other members are being contacted by email, does this lead to confusion?

Should there be a simple advice card, or a specific list that can be resourced advising reasons when PP considers emailing.
Which emails a member can respond to.
Along with the appropiate advice (time spec response by)
Fo anything else - please use the FaQ's and WB etc.

Theres nothing on the monthly statement email advising please do not respond to this message.
If you do respond some may miss Member Services >no.reply@purepla.net

Its probally a moving target....and of course I can't see the wood for the trees.