It is proper Netiquette to refrain from sharing others addresses. Don’t give out other peoples email address.
Address Sharing Netiquette For Email
Email addresses are personal contact information. Personal contact information of friends should not be shared with others because the information then becomes public.
Email Address Sharing
Ask permission before sharing personal information to keep the information personal.
Address Sharing Netiquette
Refrain from sharing addresses of others without permission because they are personal information.
To email rules.