I agree. In fact, I would go one better: Give me a button to click when I am actually
shopping and interested in ads. I mentioned this before and someone said that Google had a store, but apparently it's pretty risky to try to buy stuff there.
I also thought this is something Duck Duck Go could implement to distinguish itself. It will result in a better experience for advertisers as clicks would be pre-qualified. It's the counter-move to Google's "quality score" which, when you think about it (or actually do advertising), is anti-pre-qualification.
What I mean is this: If people are just looking for information (free) and not wanting to buy, then if I put something in my ad that discourages people from clicking (by putting in a price, for example), then I get less clicks-per-display and my quality score goes down. However, only displaying these ads to people who are looking to buy would negate that.