It seems for example for Cost-per-mille (CPM) advertising if a user has an ad-blocker, they will not see the ad, but it would still count towards the number of impressions if the ad request is made?
There's some adblockers focused on disrupting tracking and those will both intentionally load ads and automatically click on every one of them for you.
No idea of course. I couldn't tell you any anything in ALL cases.
But the ad space is dominated by a few companies and all do that as far as I know.
The other dominating ad space is spliced into videos and they certainly know you will skip around if you can on YouTube.
> If a request is made
It won't be made that's what adblockers do. Or it won't land in the case of pihole/DNS level blockers.
Otherwise it wouldn't speed up browsing and tracking would continue unhindered.