@Professional Guest, I'd say that could only be answered on a case-by-case basis.
I can tell you this. A lot of evaluators seem to feel that they have insight into what the clients might want to know. More often than not, they are wrong.
All MSC's are contracted to supply specific information and in most cases, the client only wants that information. For example; One particular chef-driven restaurant client had a large influence on how Coyle collects and reports data about food. The client was very specific about the fact that they did not want a critique of the cuisine, but instead information about how service may have affected the experience. Many evaluators, after having been assigned to this restaurant, would offer flowery descriptions of the presentation and ingredients, and subjective comments about the preparation, many of which I was required to remove as an editor.
If the client is a celebrity chef and their restaurant is hugely successful, there is a very good chance the chef feels like they have a handle on the menu. They don't want subjective input from an anonymous shopper unless their staff have somehow sullied the dining experience. If there's a hair in your food or the rare steak arrives well done, mention it. If you don't like the choice of peppers utilized in a dish or feel like foie gras is overused in high-end cuisine, you are better to keep that opinion to yourself. It will not be included in the report. There actual food critics who go to the restaurant the chef could visit Yelp if he wanted public impressions of the cuisine. Shoppers are sent in to measure very particular data points. I think you make the best impression with an MSC is you stick to those points unless an extenuating circumstance presents itself.