We can't stop them before they appear (that's down to Google), but I can ban related ad creation networks once identified. I find myself banning something like that every 4-5 weeks, but it's a tedious process to find them (helps to have the URL from the ad being shown).
However, when you see ads like that, you can also report them directly to Google by clicking the little sideways blue arrow |> at the top right. I think the X also works, although that's more intended to stop showing the ad to yourself.