hmmm well one possibility is that people simply under-reported crying more after giving the treatment.
That is a possibility, although you'd hope that a well-designed trial would make that less likely.
From my own experience, I know that we had some dreadful evenings before giving infacol, then some peaceful ones. Then we stopped the infacol and the crying started again, only to improve once infacol recommenced. I know I wasn't personally under-reporting, I was acutely aware of the difference!
Placebo or otherwise, you'd have found it quite difficult to prise it from my hands in the early days.