If you want to see the real-world impact of interchange regulations, the best place to look is obviously Australia. This is a country where the most sweeping changes to the interchange model have taken place, a country seen by regulators everywhere as something of a model to learn from.
If you can’t go to Australia to learn first-hand (maybe you've been trying to convince your boss to let you go, but he hasn't said yes yet), another way would be to look at the work of Australian research firm, East & Partners. They recently released a report, titled Australian Merchant Acquiring & Cards Markets, which shows how bad surcharging on credit card transactions has become. (See the report brochure here and the firm's press release here.)
“Surcharging is most common at the top end of town where up to 26 percent of merchants have already introduced surcharges and a further 38.7 percent are planning to do so in the coming months. In theory, the rise in surcharging should produce a shift from credit cards to other forms of payment which are relatively less costly.”
I’m looking forward to seeing the firm’s next report, which I imagine would begin to show whether or not this shift actually happens in a meaningful way.
"Dang it, Aneace!" you say with understandable anger. "Now I definitely can't convince my boss to let me go to Australia!"