It's already true at a couple of places. You pay $ for any thing over a certain amount. I forget the names but they're in DTD. I know for certain Add-ons at certain places, you will be charged a surcharge too. It depends on the restaurant.
But I can see it starting at a place like Le Cellier where you have one item at $38, 3 in the $26-7 range and 6 or 7 things $16-22. Do you make that one credit or two? Well you definitely have one item worthy of a two banger, but the rest are marginal or definitely only a one banger. So I can see them leaving it one credit, and adding a $10 surcharge (still a good deal) for the 20 oz Ribeye steak of prime grade.
I'd rather they make it one and add a surcharge myself when all is said and done rather than make it two as they were thinking and effectively shut off 3/4 of their menu.