The problem is that then noone would click on the ads any more

Acquiring ad clicks by deceiving people into thinking they aren't ads isn't an ethical business model.

I appreciate your effort on trying to putt the words 'google' and 'ethical' in the same sentence. It just doesn't fit. It's business. Who cares about the user any longer?

That only means ads don't fit anymore in this capitalistic world.. so shut them down..

Honestly, the biggest and best move Google could make is to have certain categories of search results ad-free. No search result for a financial institution should include AdWords. There's too many phishing sites that get into AdWords. Same for specific download categories. If you search for "Adobe Flash Player download", you shouldn't get any results or ads that aren't adobe.com at this point.

They could require a deposit for ads, which gets confiscated if they're found to be problematic.

I'm sure terms like that pay by far the most per click.

Is that relevant? Those cost-per-click prices would be driven up by high demand between malware and phishing site owners. If Google knowingly continues to profit off prices driven primarily by malware, doesn't that make them legally responsible for those infections? Shouldn't Google be held to some accountability for the amount of malware it distributes?