I am a firm believer in the "buffer zone". I pay a certain amount for an answering service, to handle after hour calls, and make it abundantly clear when patients use the portal, that it is only for non-emergent messages. The patients are also made aware that the portal will only be utilized by my nurse or myself during working hours.
This goes along with pharmacists, especially the local ones. They have been educated that I will respond immediately if they call the business phone during working hours. But they are not or will ever get my smart phone number, unless I choose to call them from my smart phone.
I think it is just a matter of education and maintaining one's sanity. For me having a "buffer zone" allows the business and personal to stay as separate as possible, and I am of the opinion the telephone portion of my smart phone is personal and the business phone is business, but as I have said before there is more than one way to skin a cat.