This already happened. It's why the Chromium team doesn't allow blocking video completely because they saw the advertisers just working around the issue by maki

This already happened. It's why the Chromium team doesn't allow blocking video completely because they saw the advertisers just working around the issue by making custom players. Those players were bloated and heavy so by blocking video for the user they didn't actually help block video and they made the problem worse. So yes, with or without wasm, people will roll their own ways of trying to get your attention.