To mask (cloak) e-mail found in event description text the whole description text has to be passed through "Content - Email Cloaking" plugin. This is Joomla! standard. You can do that easily with modules by checking "Prepare Content" and activating "Content - Email Cloaking" plugin. Read here for more information:
stackoverflow.com/questions/16378251/how-to-cloak-an-email-address-in-a-custom-html-module-in-joomla-3-1
Not sure what performance impact this will have if you start passing JEM-event-descriptions or custom fields through prepare content in order to cloak e-mails. Perhaps, you can have some sot of mark up agreed with your users {{emailaddress@abc.com}} for this purpose and look for that syntax whilst preparing the view? This way no need to call plugins, look for the agreed synax and use standard Joomla! function to cloak whilst processing the view:
docs.joomla.org/How_to_cloak_email_addresses
