Phishers and scammers are busy folks. One way to avoid helping them is to always use BCC if you're sending an email to more than one recipient, especially people who don't know each other. This keeps the email addresses of all recipients on the list private. Not only is it good "netiquette", but using BCC can help keep your friends safe from scammers who hijack an email account.
I'm sure many of you have friends who love to forward the email jokes and stories that they find interesting. Sometimes, in a forward, I'll receive a list of twenty or thirty email addresses that have been forwarded... and I know no one on the list but the most recent forwarder. It makes me very uncomfortable to see my email included in the list. I've explained how to use BCC to many friends and family members.
It's easy to use BCC. If you don't know how, and aren't using it, google BCC, and your service, and you'll find easy instructions.