Since you're emailing members, you really don't know what their situation is. It's tempting to believe that it's confidential person-to-person communication, but it may not.Do not use e-mail to communicate confidential or sensitive information.
Is it a husband and wife account? Is it saved on the home computer where anyone can read it? Or will it go to their smart phone while the kids are playing a game on it?
Then there's my own pet peeve: people who send a mass mailing with everyone in the "to" or "cc" fields when "bcc" would be more appropriate.