Almost three years ago, on 25/03/2013, Scarlet Vacaru answered this way to my question:
"I also had the same problem with email notifications to customers. Situation: I created a Quotation, then I Confirmed the sale. When confirming the sale, the customer was being sent an email to follow the document. And that was bad for us. I deactivated the Customer Portal and now it's alright, customers are not notified any longer. For anyone new to Openerp 7.0, the path is: Settings/Configuration/General Settings - Portal Acces - then check or uncheck the "Activate the customer portal" button. You might give a second look to see whether the customer portal is activated or not. In my situation, I thought it might be something related to social networking or to followers, but it was a false trace. Anyway, activating the customer portal has its logic: they are for sure notified when the portal is active".
link https://www.odoo.com/es_ES/forum/ayuda-1/question/how-to-avoid-sending-notifications-per-email-2489
But it doesn't work for me in odoo 8.
When I schedule a meeting (ever if the partner has Customers > Sales & Purchases > Receive Messages by Email = never) the partner receives a mail.
Is it any other no coding solution?
(deactivate portal is no the solution, neither)
Andrea