YouTube has been cracking down on viewers blocking ads in the last couple of years, notably implementing a three-strikes policy for viewers with ad-blocking extensions. It looks like the company is pushing ahead with another way to halt ad-blocking add-ons.

Several Redditors with ad-blocking browser extensions have reported (h/t: Android Police) that they’re now seeing black screens on YouTube for several seconds before their video plays. Users are reporting that these screens last for anywhere between six and ~20 seconds.

It’s believed that these black screens are ads that have been blocked by web extensions. This makes sense in light of reports that YouTube was working on server-side ad injection technology, effectively embedding the ad in the video itself to make it harder for ad blockers to skip them. So these extensions are presumably able to block the ad’s content but are unable to skip ahead to the relevant content.

YouTube hasn’t commented on this ad injection technology, but it did publish a post yesterday to claim that it was upgrading its “safety standards for browser extensions on YouTube.” The company added that these changes were made to “safeguard viewers and creators from cyber attacks such as hijacking or data theft.”

Some Redditors don’t seem too fussed about looking at a black screen for a few seconds. But between this latest event, killing YouTube Vanced, and its existing three-strikes policy, YouTube really wants you to buy YouTube Premium.