One of our mass-market ice cream brands here (Chapman's) is using "shrinkflation" in its ads, by pointing out that its 2 litre size remains 2 litres, while many others are not. It's a bit disingenuous - the reason many brands sell a 1.89 litre size is that it's two American quarts - but I'm sure it has been effective for them.
ETA: Not that this is pertinent to restaurants, of course. On the whole I'm in the "restaurant meals are too frikkin' big anyway" camp, but for a lot of eateries that's very much their brand. I can understand why customers would get upset at shinkage, but (shrug) margins have to come from somewhere.