Google representatives gave ad buyers tips on how they could reach teens, even though the company bars targeted advertisements to users under the age of 18 based on their demographics, according to a report from Adweek.

Three unnamed ad buyers told Adweek that Google sales reps suggested they might be able to reach teens by targeting a group of “unknown” users, whose “age, gender, parental status, or household income” Google doesn’t know. Adweek said it also reviewed written documents backing up the sources’ claims. A Google spokesperson told Adweek that the unknown category can include users who aren’t signed in to their accounts or who’ve turned off personalized ad targeting.

Google’s stated policy is to “block ad targeting based on the age, gender, or interests of people under 18.” The Adweek story is yet another example of Google reportedly helping ad buyers target teens through the use of its unknown user category, after the Financial Times recently reported on a similar situation.