I don't see that anything I write is all that interesting to anyone except myself. I doubt the woman I pay is all that interested in it - let alone anyone else. I don't worry about email as being un-secure when dealing with the therapist. As an attorney, the rules in my state require me to put a lengthy disclaimer on my email correspondence.

Nothing is completely secure. Regular post office mail can be intercepted and opened, paper files can be opened and stolen, phones can be tapped, medical records are being hacked, etc. So if one is going to worry about communications - worry away - but to get all worked up over email specifically does not seem worth it to me.

Agencies often do have a lot of bureaucratic busy work rules that practitioners in solo or other types of private practice can handle differently. Look at some of the silly post office rules about how long a mail carrier's stride should be and other things:
http://uspsmiscl.lettercarriernetwor...CE%20GUIDE.pdf