It recently became apparent to us that there are multiple templates for sending email. There is the one that can be customized but it only get customized for internal users. There is also a separate template for external users and it cannot be customized and is common across all reports. All templates need to be customization for each report. Since the Report Server is designed to send to anyone and the licenses are controlled by who can create reports, it makes the ability to send report to users extremely limited.