And, if the question is not asked, most of us will not bother writing in the information.
Many people fill out an evaluation in one of only two instances: they are very happy; or they are very unhappy. For all of my trips there were high spots and low spots, but the lows were not really that low. Some of the highs were really high, and I reported as such on the evaluation. For the lows, well, they were hardly worth mentioning.
Had the evaluation asked what I thought about the size of the group, I would have said, at best, it was satisfactory. Even if there were only four of us besides the driver and the PD, I would not have asked for more. The only time I mentioned that the group was too big was on the Sicily trip, and that was because of a rather marginal PD and not because of any real difficulty with the number of tourists. The PD was doing her first GCT tour (38 tourists) after having done several OAT trips with about 16 tourists. She was slightly overwhelmed by the logistics.