You're correct, my client default to reply to sender and cc the list for some reason, I have to manually move the CC to To and remove the extra To in order to reply to list. It's a bit of a pain in the ass to do for every single message, hence why I usually don't bother. Most lists check the headers and if you're already in them won't send you a second copy, so it generally doesn't matter much, I was just confused for a second cause I thought he encrypted the message to the list and that would have been bad.