Unfortunately, we are not able to support sending custom emails from within MyAnswers at this time. Doing so would open AiG up to potential abuse of the email system. It would only take one "bad apple" to cause us to be in violation of spam laws or run afoul of bulk email policies of the major email providers. We definitely do not want our domains to be blacklisted by them, which would then mark all emails coming from our domains (VBS-related or not) as spam.
Instead, you can easily collect the email address of all your registrants by going to People -> Student/Volunteers -> Click the actions dropdown menu and select "Download Full Student List". The spreadsheet that downloads will allow you to select and copy the email address column into your email client of choice.
Please let me know if I can help with anything else.
Customer support service by UserEcho