I agree that they've made questionable decisions, but if an extension is clicking on ads in the background wouldn't that be considered a violation of their ToS for related products that they control.. essentially, a way to game ad revenue? If someone released an extension to silently DDoS ad organizations in the background, even if the user was aware of the purpose, then I'd imagine it would still be against their ToS. Extensions like this can still be installed from a packed extension. I don't think Apple would do anything different if there was an app in their app store that did things in the backgrounds to violate their policies.