Left Curly Bracket Anywhere in custom Template.html breaks WP Customize Interface

Users should probably be made aware that if they add a left curly bracket in the HTML template.html file without a closing curly bracket, the Customize Admin Interface will break. I assume this is due to character matching to replace the plugin placeholders which use opening and closing curly brackets. Wondering whether pattern matching will resolve the issue and allow plugin users to use opening and or closing curly brackets in custom newsletter templates.