[Google] added that it did not have the ability to control data collection on a brand’s website after a YouTube viewer clicked on an ad. Such data-gathering, Google said, could happen when clicking on an ad on any website.

Even so, ad industry veterans said they had found it difficult to prevent their clients’ YouTube ads from appearing on children’s videos, according to recent Times interviews with 10 senior employees at ad agencies and related companies. And they argued that YouTube’s ad placement had put prominent consumer brands at risk of compromising children’s privacy.

The argument was already put forth that Alphabet can't control what's on the advertisers' sites. But for a company that loves hoovering up data they seem to have picked an interesting blind spot that their algorithms can't fine- tune for. And they of course always have the choice to not run ads for websites that deposit a deluge of trackers, but that would mean revenue down, big sad.

No need to be presumptuous. Hackernews doesn't allow parents to downvote replies.

Huh? Why would you think it's not in Google's best interest -- from an ethical, business and perhaps legal standpoint-- to police what its advertisers do?

Or did you forget about Analytics.