Ever since email was first invented most of what you read tells you that should never reveal personal or private information in emails because emails are insecure.
One thing I've learnt about the technology industry, just because something maybe the situation at one stage doesn't mean to say it will always remain like that.
That's what's happened with the emails.
According to this article emails are now a lot more secure than they used to be.
It's basically saying that the messages themselves are now secure but still ther are problems with security with emails from pilfering attacks. That is when you receive an email you're not sure that it's actually come from the person that shows as being sent at the top of the message.
Another thing I've learnt about reading any material is to also check how old the material is. In the case of the above article it was written 3 years ago. A lot of things have happened since then.
Further research reveals but because of Sender Privacy Framework (SPF)
https://en.m.wikipedia.org/wiki/Sender_Policy_Framework
technology, pilfering attacks are far less likely to happen.
Does that now mean it's ok to put whatever you like in a email and you know it is 100% secure. Nothing is 100% secure. All of life is a risk.
Remember the old adage if you wanted to spread information around you just gave it to somebody that you knew was a bit of a mouth and said don't tell anybody about this, but…
If you send somebody an email you don't know what they're going to do with it.
But then there's the relativity aspect. It's a lot more secure to send an email to a person then using Facebook to direct the message towards one person but end up spreading it to the whole Facebook audience
It's all a matter having some appreciation of how the technology works. What you don't know can hurt you.