More like I'm arguing that if they use their BG detection for catching adblockers as well, then that part _might_ be attacked with a greater force than before - and if broken, might hurt them more than adblockers did. Of course it's just pure speculation.
Back to the technical argument, I was refering to the fact that a DB read to check if an ad should be served (done on the player page) as well as the DB write to check if the video was downloaded earlier (on the CDN, we have signatures there and expiry date passed as a parameter) might be infeasible from the architectural/performance point of view, but I gotta admit I actually don't have any relevant knowledge here so I'm just speculating because this seems interesting.
It would be done in-memory on whatever server the load-balancer assigns the visitor to, at the same time that the request is checked for permissions anyway. Compared to the rest of the data Google collects the extra timestamp isn't even a rounding-error and doesn't need to be persisted in long-term storage (the request is in the logs anyway).
Back to the technical argument, I was refering to the fact that a DB read to check if an ad should be served (done on the player page) as well as the DB write to check if the video was downloaded earlier (on the CDN, we have signatures there and expiry date passed as a parameter) might be infeasible from the architectural/performance point of view, but I gotta admit I actually don't have any relevant knowledge here so I'm just speculating because this seems interesting.