Just tell your kids not to fill out the demographic, personal, and career type questions when creating ACT and Collegeboard accounts and/or registering for tests…many of those ?’s are optional. Also tell them to opt out of the collegeboard’s ‘scholarship search’…such BS.
Selling/Purchasing mailing lists is a generally accepted marketing activity in many industries, but you don’t have to make it easy for them. Colleges sell each other their own mailing lists too.