Recently, a parent who was registering for one of our events put two email addresses into the email field. She separated them by a comma. It is not uncommon that email fields allow more than one address separated by a comma.

Unfortunately, because she did this, her email somehow got triggered for Blackbaud's "black list." That meant she could no longer receive emails from GDS. To rectify this, I had to learn about the problem by getting the black list via a support ticket and then have her email unblockme@blackbaud.com. These seem like a pretty drastic "penalty" to putting two email addresses into an email field.

This could be solved by adding logic to the email field for event registrations. If someone adds info that doesn't look like a valid email, give them an error message rather than accepting the data and then blacklisting the user.