When an engineer at tech company Golden Frog discovered that his Internet provider had stripped out an essential security email security feature, he revealed a very confusing security practice.
First, a little background:
Whenever you send an email, it can be flagged with certain security protocols. The one you need to keep an email private is called STARTTLS.
If an email client has STARTTLS enabled, then an extra layer of security keeps emails sent on public network private and encrypted.
What the Golden Frog engineer discovered was that STARTTLS occasionally didn't work when he sent emails on his laptop while using his smartphone as a Wi-Fi hotspot.