i would assume they've spent decades working around that one. there's a lot of ways they could potentially try to handle that, from locking down the video player controls to delaying your fast forward until after the ad to completely changing the embedded media player for the ad despite the video stream being continuous. if they still have the skip ads button like currently, i'd imagine that becomes literally just letting you jump ahead to the end. they already will have to account for the normal video playback stuff. all of this is the reason they tried to not do things this way until now. dealing with all of that is part of what makes it computationally intensive to shove in the ads on the fly.