Abandonment & Coupon/Discount Phishing

I just took over support for an existing site and the owner said they previously used an extension to handle abandoned carts. He said they quit using it because most people learned to abandon their carts and just wait for a coupon/discount to arrive. I'm sure part of this was configuration and another part could have been the extension.

Does anyone know an extension that handles customers that constantly wait for abaonded coupons to arrive? I know we could kind of handle this basing discount/coupons on the amount of the cart, certain items, and random mailings, but seems like there should be a better way to catch abusers.