So, there's been a lot of reviewing going on during DIB and there seems to be two schools of thought:
1) A restaurant should be able to offer a super low cost meal, have it executed perfectly, for double to triple the number of customers, while being served by waiters who are used to making way more money interacting with more educated diners.
2) A restaurant is opening its doors for a fraction of the price to people who are either too cheap or too stupid to know where to eat during other times of the year and therefor aren't held accountable to regular standards.
The fact of the matter is that no restaurant wants to be involved in DIB. For restaurants that are already reputable and doing well, they simply don't need the extra business and, if anything, can have their reps tainted by rolling out "more simply prepared" food. The waiters know that 95% of their guests won't come back anyway and won't tip over 15% no matter how well they serve. The chefs are all preparing the same dishes hundreds of times and simply can't (b/c they're human) execute with the same level of precision as a regular "plain ole' busy night." That's from the restaurant side.
From the diner's side- if the restaurant is involving itself in DIB, then they should deliver on their promise to offer good food with good service. It's not the diner's problem if the waiter is too busy or the chefs mired in monotony. The guest should still get a good meal and be served with attention.
The reason, however, why neither argument is applicable to merit an actual review OF THE INTEGRITY OF THE RESTAURANT, is that DIB is not a typical day at the office. Have you ever dealt with your accountant in September then tried getting them on the phone in March? Same deal.
For those of you looking for answers as to which restaurants to patronize, don't trust the judgment of DIB bloggers. If you've heard relatively good things about a place, seen it reviewed well by Zagat, New York Mag, New York Times, etc, go DURING THE WEEK (not the weekend) and order well off their normal menu (or, even better, their tasting menu). In other words, get an appetizer and entree per person, a bottle of wine in the $40 range, and at least share a dessert.
Then if you STILL have a shitty time, then it's probably a shitty restaurant.