Well many adblockers can be clever enough to load the asset, but then just drop it. As in yeah the ad image got downloaded to browser, but then the page content got edited to drop the display of the add or turn it to not shown asset in css.

This is age old battle. Site owners go you must do X or no media. However then ad blocker just goes "sure we do that, but then we just ghost the ad to the user".

Some script needs to be loaded, that would display the ad? All the parts of the script get executed and.... then CSS intervention just ghosts the ad that should be playing and so on.

Since the browser and extension are in ultimate control. As said the actual add video might be technically "playing" in the background going through motions, but it's a no show, no audio player.... ergo in practice the ad was blocked, while technically completely executed.

Hence why they want to scan for the software, since only way they can be sure ad will be shown is by verifying a known adhering to showing the ad software stack.

Well EU says that is not allowed, because privacy. Ergo the adblocker prevention is playing a losing battle. Whatever they do on the "make sure ad is shown" side, adblocker maker will just implement counter move.