What nonsense. The group could only reply to the questions they were being asked. There is nothing odd about them not knowing exactly what they did on each day of the holiday - as they had no idea that it was ever going to be important - so had no reason to make sure they remembered.
Could you give a detailed description with exact times etc of what you did every minute of every day last week? I certainly couldn't.
Last week? probably not. I lost someone on the 20th of March 2007 and can tell you that Mother's day fell on the 18th of March that year. That comic relief was on 16th, that my son had football training on the 15 and it was freezing cold, that we bought chips on the way home. On the Monday of that week, so that would be the 12th, it was parents evening.
On Tuesday the 20th a surveyor was due at my house. It was sunny. My younger son was going to his friends house for dinner straight from school.
When something significant happens you do tend to remember the surrounding events.