Email communications are important. When you deal professionally with email, you and your company will have an important competitive edge. Additionally, by educating employees, you protect your company from awkward liability issues.
Reply to all
If you are cc:ed on an e-mail and want to respond only to the sender, it isn’t necessary to Reply To All. If you do, then every one of the recipients will receive your e-mail. It may be more appropriate to simply press the Reply button so your response goes only to the original sender.